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Diffstat (limited to 'libnetutil/EthernetHeader.cc')
| -rw-r--r-- | libnetutil/EthernetHeader.cc | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/libnetutil/EthernetHeader.cc b/libnetutil/EthernetHeader.cc new file mode 100644 index 0000000..5daa3f1 --- /dev/null +++ b/libnetutil/EthernetHeader.cc @@ -0,0 +1,219 @@ +/*************************************************************************** + * 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) 1996-2023 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 "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 || len<ETH_HEADER_LEN){ + return OP_FAILURE; + }else{ + this->reset(); /* 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() */ + |