/*************************************************************************** * EthernetHeader.cc -- The EthernetHeader Class represents an Ethernet * * header and footer. It contains methods to set the different header * * fields. These methods tipically perform the necessary error checks and * * byte order conversions. * * * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * The Nmap Security Scanner is (C) 1996-2024 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 "EthernetHeader.h" /******************************************************************************/ /* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */ /******************************************************************************/ EthernetHeader::EthernetHeader(){ this->reset(); } /* End of EthernetHeader constructor */ EthernetHeader::~EthernetHeader(){ } /* End of EthernetHeader destructor */ /** Sets every attribute to its default value */ void EthernetHeader::reset(){ memset(&this->h, 0, sizeof(nping_eth_hdr_t)); this->length=ETH_HEADER_LEN; } /* End of reset() */ /** @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 * EthernetHeader::getBufferPointer(){ return (u8*)(&h); } /* End of getBufferPointer() */ /******************************************************************************/ /* PacketElement:: OVERWRITTEN METHODS */ /******************************************************************************/ /** Stores supplied packet in the internal buffer so the information * can be accessed using the standard get & set methods. * @warning The EthernetHeader class is able to hold a maximum of 14 bytes. * If the supplied buffer is longer than that, only the first 14 bytes will be * stored in the internal buffer. * @warning Supplied len MUST be at least 14 bytes (Ethernet header length). * @return OP_SUCCESS on success and OP_FAILURE in case of error */ int EthernetHeader::storeRecvData(const u8 *buf, size_t len){ if(buf==NULL || lenreset(); /* Re-init the object, just in case the caller had used it already */ this->length=ETH_HEADER_LEN; memcpy(&(this->h), buf, ETH_HEADER_LEN); } return OP_SUCCESS; } /* 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 EthernetHeader::protocol_id() const { return HEADER_TYPE_ETHERNET; } /* 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 EthernetHeader::validate(){ if( this->length!=ETH_HEADER_LEN) return OP_FAILURE; else return ETH_HEADER_LEN; } /* 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 EthernetHeader::print(FILE *output, int detail) const { fprintf(output, "Eth["); for(int i=0; i<6; i++){ fprintf(output, "%02x", this->h.eth_smac[i]); if(i<5) fprintf(output, ":"); } fprintf(output, " > "); for(int i=0; i<6; i++){ fprintf(output, "%02x", this->h.eth_dmac[i]); if(i<5) fprintf(output, ":"); } if(detail>=PRINT_DETAIL_MED) fprintf(output, " Type=%04x", this->getEtherType()); fprintf(output, "]"); if(this->next!=NULL){ print_separator(output, detail); next->print(output, detail); } return OP_SUCCESS; } /* End of print() */ /******************************************************************************/ /* PROTOCOL-SPECIFIC METHODS */ /******************************************************************************/ /** Sets Source MAC address * @warning Supplied buffer must contain at least 6 bytes */ int EthernetHeader::setSrcMAC(const u8 *m){ if(m==NULL) netutil_fatal("EthernetHeader::setSrcMAC(u8*): NULL value supplied "); memcpy(h.eth_smac, m, 6); return OP_SUCCESS; } /* End of setSrcMAC() */ /** Returns source port in HOST byte order * @warning Returned pointer points directly to a Class internal buffer. If * contents are changed, the instance of the class will be affected. */ const u8* EthernetHeader::getSrcMAC() const { return this->h.eth_smac; } /* End of getSrcMAC() */ /** Sets Destination MAC address * @warning Supplied buffer must contain at least 6 bytes */ int EthernetHeader::setDstMAC(u8 *m){ if(m==NULL) netutil_fatal("EthernetHeader::setDstMAC(u8 *): NULL value supplied "); memcpy(h.eth_dmac, m, 6); return OP_SUCCESS; } /* End of setDstMAC() */ /** Returns destination port in HOST byte order */ const u8 *EthernetHeader::getDstMAC() const { return this->h.eth_dmac; } /* End of getDstMAC() */ int EthernetHeader::setEtherType(u16 val){ h.eth_type=htons(val); return OP_SUCCESS; } /* End of setEtherType() */ /** Returns destination port in HOST byte order */ u16 EthernetHeader::getEtherType() const { return ntohs(this->h.eth_type); } /* End of getEtherType() */