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+/***************************************************************************
+ * HopByHopHeader.cc -- The HopByHopHeader 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 "HopByHopHeader.h"
+#include <assert.h>
+
+/******************************************************************************/
+/* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */
+/******************************************************************************/
+HopByHopHeader::HopByHopHeader() {
+ this->reset();
+} /* End of HopByHopHeader constructor */
+
+
+HopByHopHeader::~HopByHopHeader() {
+
+} /* End of HopByHopHeader destructor */
+
+
+/** Sets every attribute to its default value */
+void HopByHopHeader::reset(){
+ memset(&this->h, 0, sizeof(nping_ipv6_ext_hopbyhop_hdr_t));
+ curr_option=(u8*)this->h.options;
+ this->length=2;
+ this->addOption(EXTOPT_PADN, 4, (const u8*)"\x00\x00\x00\x00");
+} /* 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 *HopByHopHeader::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 HopByHopHeader 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 HopByHopHeader::storeRecvData(const u8 *buf, size_t len){
+ if(buf==NULL || len<HOPBYHOP_MIN_HEADER_LEN){
+ this->length=0;
+ return OP_FAILURE;
+ }else{
+ /* Store the first 4 bytes, so we can access the HdrExtLen field. */
+ memcpy(&(this->h), buf, 4);
+
+ /* Check that the HdrExtLen field makes sense:
+ * 1) Check that it carries as many octets as it claims
+ * 2) Check that we don't exceed our internal storage space. */
+ // h.len cannot exceed 0xff, so max is (0xff+1)*8, but HOPBYHOP_MAX_HEADER_LEN is 8 + 0x100*8
+ if( ((unsigned int)(this->h.len+1))*8 > len){
+ this->length=0;
+ return OP_FAILURE;
+ }else{
+ int mylen=(this->h.len+1)*8;
+ this->reset();
+ this->length=mylen;
+ memcpy(&(this->h), buf, this->length);
+ return OP_SUCCESS;
+ }
+ }
+ return OP_FAILURE;
+} /* 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 HopByHopHeader::protocol_id() const {
+ return HEADER_TYPE_IPv6_HOPOPT;
+} /* 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 HopByHopHeader::validate(){
+ nping_ipv6_ext_hopbyhop_opt_t *curr_opt=NULL;
+ u8 *curr_pnt=(u8 *)this->h.options;
+ int bytes_left=this->length-2;
+
+ /* Check the object's length makes sense*/
+ if(this->length%8!=0 || this->length < HOPBYHOP_MIN_HEADER_LEN || this->length > HOPBYHOP_MAX_HEADER_LEN){
+ return OP_FAILURE;
+ }
+ /* Check the header's length field. It should match the object's length */
+ if( (this->h.len+1)*8 != this->length){
+ return OP_FAILURE;
+ }
+
+ /* Now validate the TLV-encoded options. */
+ while(bytes_left>0){
+ /* Use the opts structure as a template to access current option */
+ curr_opt=(nping_ipv6_ext_hopbyhop_opt_t *)curr_pnt;
+
+ /* Let's see what we have. */
+ switch(curr_opt->type){
+
+ /* Pad1
+ +-+-+-+-+-+-+-+-+
+ | 0 |
+ +-+-+-+-+-+-+-+-+ */
+ case EXTOPT_PAD1:
+ curr_pnt++; /* Skip one octet */
+ bytes_left++;
+ break;
+
+ /* PadN
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -
+ | 1 | Padding Len | Padding
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - */
+ case EXTOPT_PADN:
+ /* Check we have as many octets as the option advertises */
+ if(bytes_left<2+curr_opt->len)
+ return OP_FAILURE;
+ curr_pnt+=2+curr_opt->len;
+ bytes_left-=2+curr_opt->len;
+ break;
+
+ /* Jumbo Payload Option (RFC 2675).
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Option Type | Opt Data Len |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Jumbo Payload Length |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
+ case EXTOPT_JUMBO:
+ /* Jumbo has a fixed length of 4 octets (plus 2). */
+ if(curr_opt->len!=4)
+ return OP_FAILURE;
+ /* Check if we actually have all the octets */
+ if(bytes_left<2+4)
+ return OP_FAILURE;
+ curr_pnt+=6;
+ bytes_left-=6;
+ break;
+
+ /* Tunnel Encapsulation limit (RFC 2473).
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Option Type | 1 | Tun Encap Lim |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
+ case EXTOPT_TUNENCAPLIM:
+ /* This one also has a fixed length. */
+ if(curr_opt->len!=1)
+ return OP_FAILURE;
+ /* Check if we actually have all the octets */
+ if(bytes_left<2+1)
+ return OP_FAILURE;
+ curr_pnt+=3;
+ bytes_left-=3;
+ break;
+
+ /* Router Alert (RFC 2711).
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Option Type | 2 | Value (2 octets) |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
+ case EXTOPT_ROUTERALERT:
+ /* Fixed length (two octets)*/
+ if(curr_opt->len!=2)
+ return OP_FAILURE;
+ /* Check that we actually have all the octets */
+ if(bytes_left<2+2)
+ return OP_FAILURE;
+ curr_pnt+=4;
+ bytes_left-=4;
+ break;
+
+ /* Quick-Start (RFC 4782).
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Option | Length=6 | Func. | Rate | Not Used |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | QS Nonce | R |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
+ case EXTOPT_QUICKSTART:
+ /* Fixed length (two octets)*/
+ if(curr_opt->len!=6)
+ return OP_FAILURE;
+ /* Check that we actually have all the octets */
+ if(bytes_left<2+6)
+ return OP_FAILURE;
+ curr_pnt+=8;
+ bytes_left-=8;
+ break;
+
+ /* CALIPSO (RFC 5570).
+ +----------------------------+
+ | Option Type | Option Length|
+ +-------------+---------------+-------------+--------------+
+ | CALIPSO Domain of Interpretation |
+ +-------------+---------------+-------------+--------------+
+ | Cmpt Length | Sens Level | Checksum (CRC-16) |
+ +-------------+---------------+-------------+--------------+
+ | Compartment Bitmap (Optional; variable length) |
+ +-------------+---------------+-------------+--------------+ */
+ case EXTOPT_CALIPSO:
+ /* The length of the CALIPSO option is variable because the
+ * Compartment Bitmap is not mandatory. However, the length
+ * must be at least 8. */
+ if(curr_opt->len<8)
+ return OP_FAILURE;
+ /* Check that we actually have all the octets */
+ if(bytes_left<2+curr_opt->len)
+ return OP_FAILURE;
+ curr_pnt+=2+curr_opt->len;
+ bytes_left-=2+curr_opt->len;
+ break;
+
+
+ /* Home Address (RFC 6275).
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Option Type | Option Length |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | |
+ + +
+ | |
+ + Home Address +
+ | |
+ + +
+ | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*/
+ case EXTOPT_HOMEADDR:
+ /* Fixed length of 16 */
+ if(curr_opt->len!=16)
+ return OP_FAILURE;
+ /* Check if we actually have all the octets */
+ if(bytes_left<2+16)
+ return OP_FAILURE;
+ curr_pnt+=18;
+ bytes_left-=18;
+ break;
+
+ /* Option Type Unknown */
+ default:
+ /* If we don't know the option, we can still try to validate it,
+ * checking if the OptionLength contains something reasonable. */
+ /* Fixed length of 16 */
+ if(bytes_left<2+curr_opt->len)
+ return OP_FAILURE;
+ curr_pnt+=2+curr_opt->len;
+ bytes_left-=2+curr_opt->len;
+ break;
+ }
+ }
+ 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 HopByHopHeader::print(FILE *output, int detail) const {
+ fprintf(output, "HopByHop[%d,%d]", this->h.nh, this->h.len);
+ // 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 HopByHopHeader::setNextHeader(u8 val){
+ this->h.nh = val;
+ return OP_SUCCESS;
+} /* End of setNextHeader() */
+
+
+/** Returns next header id */
+u8 HopByHopHeader::getNextHeader(){
+ return this->h.nh;
+} /* End of getNextHeader() */
+
+
+/* Add TLV encoded option */
+int HopByHopHeader::addOption(u8 type, u8 len, const u8 *data){
+ /* Make sure we don't screw up due to buffer length issues */
+ if(data==NULL)
+ return OP_FAILURE;
+ if ( (this->length+len+2) > HOPBYHOP_MAX_HEADER_LEN ) /* No space for more */
+ return OP_FAILURE;
+
+ /* Store the option */
+ curr_option[0]=type;
+ curr_option[1]=len;
+ memcpy(curr_option+2, data, len);
+ /* Update internal option offset and object's length */
+ curr_option+=(len+2);
+ this->length+=(len+2);
+ this->addPadding();
+ return OP_SUCCESS;
+
+} /* End of addOption() */
+
+
+/* If the current length of the extension header is not a multiple of 8 octets,
+ * this method adds the necessary padding (either PadN or Pad1 options)*/
+int HopByHopHeader::addPadding(){
+ u8 zeroes[8]={0,0,0,0,0,0,0,0};
+ // required_octets in range [0,7]
+ int required_octets=(8 - (this->length % 8)) % 8;
+
+ /* Make sure we have enough space for the padding. */
+ if ( (this->length+required_octets) > HOPBYHOP_MAX_HEADER_LEN )
+ return OP_FAILURE;
+
+ /* Insert Pad1 or PadN to fill the necessary octets */
+ if (required_octets == 1) {
+ curr_option[0]=EXTOPT_PAD1;
+ curr_option++;
+ this->length++;
+ }
+ else if (required_octets > 0) {
+ this->addOption(EXTOPT_PADN, required_octets-2, zeroes );
+ }
+ assert(this->length%8==0);
+ this->h.len=(this->length/8)-1;
+ return OP_SUCCESS;
+} /* End of addPadding() */
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