/*************************************************************************** * TransportLayerElement.cc -- Class TransportLayerElement is a generic * * class that represents a transport layer protocol header. Classes like * * TCPHeader or UDPHeader inherit from it. * * * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2011 Insecure.Com LLC. Nmap is * * also a registered trademark of Insecure.Com LLC. This program is free * * software; you may redistribute and/or modify it under the terms of the * * GNU General Public License as published by the Free Software * * Foundation; Version 2 with the clarifications and exceptions described * * below. This guarantees your right to use, modify, and redistribute * * this software under certain conditions. If you wish to embed Nmap * * technology into proprietary software, we sell alternative licenses * * (contact sales@insecure.com). Dozens of software vendors already * * license Nmap technology such as host discovery, port scanning, OS * * detection, and version detection. * * * * Note that the GPL places important restrictions on "derived works", yet * * it does not provide a detailed definition of that term. To avoid * * misunderstandings, we consider an application to constitute a * * "derivative work" for the purpose of this license if it does any of the * * following: * * o Integrates source code from Nmap * * o Reads or includes Nmap copyrighted data files, such as * * nmap-os-db or nmap-service-probes. * * o Executes Nmap and parses the results (as opposed to typical shell or * * execution-menu apps, which simply display raw Nmap output and so are * * not derivative works.) * * o Integrates/includes/aggregates Nmap into a proprietary executable * * installer, such as those produced by InstallShield. * * o Links to a library or executes a program that does any of the above * * * * The term "Nmap" should be taken to also include any portions or derived * * works of Nmap. This list is not exclusive, but is meant to clarify our * * interpretation of derived works with some common examples. Our * * interpretation applies only to Nmap--we don't speak for other people's * * GPL works. * * * * If you have any questions about the GPL licensing restrictions on using * * Nmap in non-GPL works, we would be happy to help. As mentioned above, * * we also offer alternative license to integrate Nmap into proprietary * * applications and appliances. These contracts have been sold to dozens * * of software vendors, and generally include a perpetual license as well * * as providing for priority support and updates as well as helping to * * fund the continued development of Nmap technology. Please email * * sales@insecure.com for further information. * * * * As a special exception to the GPL terms, Insecure.Com LLC grants * * permission to link the code of this program with any version of the * * OpenSSL library which is distributed under a license identical to that * * listed in the included docs/licenses/OpenSSL.txt file, and distribute * * linked combinations including the two. You must obey the GNU GPL in all * * respects for all of the code used other than OpenSSL. If you modify * * this file, you may extend this exception to your version of the file, * * but you are not obligated to do so. * * * * If you received these files with a written license agreement or * * contract stating terms other than the terms above, then that * * alternative license agreement takes precedence over these comments. * * * * 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 (none * * have been found so far). * * * * Source code also allows you to port Nmap to new platforms, fix bugs, * * and add new features. You are highly encouraged to send your changes * * to nmap-dev@insecure.org for possible incorporation into the main * * distribution. By sending these changes to Fyodor or one of the * * Insecure.Org development mailing lists, it is assumed that you are * * offering the Nmap Project (Insecure.Com LLC) the unlimited, * * non-exclusive right to reuse, modify, and relicense the code. Nmap * * will always be available Open Source, but this is important because the * * inability to relicense code has caused devastating problems for other * * Free Software projects (such as KDE and NASM). We also occasionally * * relicense the code to third parties as discussed above. If you wish to * * specify special license conditions of your contributions, just say so * * when you send them. * * * * This program 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. See the GNU * * General Public License v2.0 for more details at * * http://www.gnu.org/licenses/gpl-2.0.html , or in the COPYING file * * included with Nmap. * * * ***************************************************************************/ /* This code was originally part of the Nping tool. */ #include "TransportLayerElement.h" #include "IPv4Header.h" #include "IPv6Header.h" /** Computes and returns the Internet checksum. * @warning This method requires the object to be linked to either an IPv6Header * object or an IPv4Header one, so the caller must ensure that objects are * properly linked with calls to setNextElement() like this: * * IPv6Header ip6; * TCPHeader tcp; * [...] # Set header fields * ip6.setNextElement(&tcp); * tcp.setSum(); * * Note that there can be a number of other headers (like IPv6 extension headers) * between the transport header and the network one, but all of them need to * be linked in order for this method to traverse the list of headers and find * the IP source and destination address, required to compute the checksum. So * things like the following are OK: * * IPv6Header ip6; * HopByHopHeader hop; * RoutingHeader rte; * FragmentHeader frg; * UDPHeader udp; * [...] # Set whatever header fields you need * ip6.setNextElement(&hop); * hop.setNextElement(&rte); * rte.setNextElement(&frg); * frg.setNextElement(&udp); * udp.setSum(); # setSum() will be able to reach the IPv6Header. */ u16 TransportLayerElement::compute_checksum(){ PacketElement *hdr; hdr=this->getPrevElement(); u16 final_sum=0; /* Traverse the list of headers backwards until we find an IP header */ while(hdr!=NULL){ if (hdr->protocol_id()==HEADER_TYPE_IPv6){ IPv6Header *v6hdr=(IPv6Header *)hdr; struct in6_addr i6src, i6dst; memcpy(i6src.s6_addr, v6hdr->getSourceAddress(), 16); memcpy(i6dst.s6_addr, v6hdr->getDestinationAddress(), 16); u8 *buff=(u8 *)safe_malloc(this->getLen()); this->dumpToBinaryBuffer(buff, this->getLen()); final_sum=ipv6_pseudoheader_cksum(&i6src, &i6dst, this->protocol_id(), this->getLen(), buff); free(buff); return final_sum; }else if(hdr->protocol_id()==HEADER_TYPE_IPv4){ IPv4Header *v4hdr=(IPv4Header *)hdr; struct in_addr i4src, i4dst; memcpy(&(i4src.s_addr), v4hdr->getSourceAddress(), 4); memcpy(&(i4dst.s_addr), v4hdr->getDestinationAddress(), 4); u8 *buff=(u8 *)safe_malloc(this->getLen()); this->dumpToBinaryBuffer(buff, this->getLen()); final_sum=ipv4_pseudoheader_cksum(&i4src, &i4dst, this->protocol_id(), this->getLen(), buff); free(buff); return final_sum; }else{ hdr=hdr->getPrevElement(); } } return 0; } /* End of setSum() */