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221 lines
8.6 KiB
C++
221 lines
8.6 KiB
C++
/***************************************************************************
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* EthernetHeader.cc -- The EthernetHeader Class represents an Ethernet *
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* header and footer. It contains methods to set the different header *
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* fields. These methods tipically perform the necessary error checks and *
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* byte order conversions. *
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* *
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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 "EthernetHeader.h"
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/******************************************************************************/
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/* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */
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/******************************************************************************/
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EthernetHeader::EthernetHeader(){
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this->reset();
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} /* End of EthernetHeader constructor */
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EthernetHeader::~EthernetHeader(){
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} /* End of EthernetHeader destructor */
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/** Sets every attribute to its default value */
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void EthernetHeader::reset(){
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memset(&this->h, 0, sizeof(nping_eth_hdr_t));
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this->length=ETH_HEADER_LEN;
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} /* End of reset() */
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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 * EthernetHeader::getBufferPointer(){
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return (u8*)(&h);
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} /* End of getBufferPointer() */
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/******************************************************************************/
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/* PacketElement:: OVERWRITTEN METHODS */
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/******************************************************************************/
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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 EthernetHeader class is able to hold a maximum of 14 bytes.
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* If the supplied buffer is longer than that, only the first 14 bytes will be
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* stored in the internal buffer.
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* @warning Supplied len MUST be at least 14 bytes (Ethernet header length).
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* @return OP_SUCCESS on success and OP_FAILURE in case of error */
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int EthernetHeader::storeRecvData(const u8 *buf, size_t len){
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if(buf==NULL || len<ETH_HEADER_LEN){
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return OP_FAILURE;
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}else{
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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=ETH_HEADER_LEN;
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memcpy(&(this->h), buf, ETH_HEADER_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 EthernetHeader::protocol_id() const {
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return HEADER_TYPE_ETHERNET;
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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 EthernetHeader::validate(){
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if( this->length!=ETH_HEADER_LEN)
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return OP_FAILURE;
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else
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return ETH_HEADER_LEN;
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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 EthernetHeader::print(FILE *output, int detail) const {
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fprintf(output, "Eth[");
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for(int i=0; i<6; i++){
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fprintf(output, "%02x", this->h.eth_smac[i]);
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if(i<5)
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fprintf(output, ":");
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}
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fprintf(output, " > ");
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for(int i=0; i<6; i++){
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fprintf(output, "%02x", this->h.eth_dmac[i]);
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if(i<5)
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fprintf(output, ":");
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}
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if(detail>=PRINT_DETAIL_MED)
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fprintf(output, " Type=%04x", this->getEtherType());
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fprintf(output, "]");
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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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/** Sets Source MAC address
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* @warning Supplied buffer must contain at least 6 bytes */
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int EthernetHeader::setSrcMAC(const u8 *m){
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if(m==NULL)
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netutil_fatal("EthernetHeader::setSrcMAC(u8*): NULL value supplied ");
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memcpy(h.eth_smac, m, 6);
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return OP_SUCCESS;
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} /* End of setSrcMAC() */
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/** Returns source port in HOST byte order
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* @warning Returned pointer points directly to a Class internal buffer. If
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* contents are changed, the instance of the class will be affected. */
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const u8* EthernetHeader::getSrcMAC() const {
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return this->h.eth_smac;
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} /* End of getSrcMAC() */
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/** Sets Destination MAC address
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* @warning Supplied buffer must contain at least 6 bytes */
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int EthernetHeader::setDstMAC(u8 *m){
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if(m==NULL)
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netutil_fatal("EthernetHeader::setDstMAC(u8 *): NULL value supplied ");
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memcpy(h.eth_dmac, m, 6);
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return OP_SUCCESS;
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} /* End of setDstMAC() */
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/** Returns destination port in HOST byte order */
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const u8 *EthernetHeader::getDstMAC() const {
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return this->h.eth_dmac;
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} /* End of getDstMAC() */
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int EthernetHeader::setEtherType(u16 val){
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h.eth_type=htons(val);
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return OP_SUCCESS;
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} /* End of setEtherType() */
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/** Returns destination port in HOST byte order */
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u16 EthernetHeader::getEtherType() const {
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return ntohs(this->h.eth_type);
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} /* End of getEtherType() */
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