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190 lines
12 KiB
C++
190 lines
12 KiB
C++
/***************************************************************************
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* TransportLayerElement.cc -- Class TransportLayerElement is a generic *
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* class that represents a transport layer protocol header. Classes like *
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* TCPHeader or UDPHeader inherit from it. *
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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) 1996-2013 Insecure.Com LLC. Nmap is *
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* also a registered trademark of Insecure.Com LLC. This program is free *
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* software; you may redistribute and/or modify it under the terms of the *
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* GNU General Public License as published by the Free Software *
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* Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE CLARIFICATIONS *
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* AND EXCEPTIONS DESCRIBED HEREIN. This guarantees your right to use, *
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* modify, and redistribute this software under certain conditions. If *
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* you wish to embed Nmap technology into proprietary software, we sell *
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* alternative licenses (contact sales@nmap.com). Dozens of software *
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* vendors already license Nmap technology such as host discovery, port *
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* scanning, OS detection, version detection, and the Nmap Scripting *
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* Engine. *
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* *
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* Note that the GPL places important restrictions on "derivative works", *
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* yet it does not provide a detailed definition of that term. To avoid *
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* misunderstandings, we interpret that term as broadly as copyright law *
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* allows. For example, we consider an application to constitute a *
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* derivative work for the purpose of this license if it does any of the *
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* following with any software or content covered by this license *
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* ("Covered Software"): *
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* *
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* o Integrates source code from Covered Software. *
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* *
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* o Reads or includes copyrighted data files, such as Nmap's nmap-os-db *
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* or nmap-service-probes. *
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* *
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* o Is designed specifically to execute Covered Software and parse the *
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* results (as opposed to typical shell or execution-menu apps, which will *
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* execute anything you tell them to). *
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* *
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* o Includes Covered Software in a proprietary executable installer. The *
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* installers produced by InstallShield are an example of this. Including *
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* Nmap with other software in compressed or archival form does not *
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* trigger this provision, provided appropriate open source decompression *
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* or de-archiving software is widely available for no charge. For the *
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* purposes of this license, an installer is considered to include Covered *
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* Software even if it actually retrieves a copy of Covered Software from *
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* another source during runtime (such as by downloading it from the *
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* Internet). *
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* *
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* o Links (statically or dynamically) to a library which does any of the *
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* above. *
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* *
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* o Executes a helper program, module, or script to do any of the above. *
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* *
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* This list is not exclusive, but is meant to clarify our interpretation *
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* of derived works with some common examples. Other people may interpret *
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* the plain GPL differently, so we consider this a special exception to *
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* the GPL that we apply to Covered Software. Works which meet any of *
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* these conditions must conform to all of the terms of this license, *
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* particularly including the GPL Section 3 requirements of providing *
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* source code and allowing free redistribution of the work as a whole. *
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* *
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* As another special exception to the GPL terms, Insecure.Com LLC grants *
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* permission to link the code of this program with any version of the *
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* OpenSSL library which is distributed under a license identical to that *
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* listed in the included docs/licenses/OpenSSL.txt file, and distribute *
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* linked combinations including the two. *
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* *
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* Any redistribution of Covered Software, including any derived works, *
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* must obey and carry forward all of the terms of this license, including *
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* obeying all GPL rules and restrictions. For example, source code of *
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* the whole work must be provided and free redistribution must be *
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* allowed. All GPL references to "this License", are to be treated as *
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* including the terms and conditions of this license text as well. *
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* *
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* Because this license imposes special exceptions to the GPL, Covered *
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* Work may not be combined (even as part of a larger work) with plain GPL *
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* software. The terms, conditions, and exceptions of this license must *
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* be included as well. This license is incompatible with some other open *
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* source licenses as well. In some cases we can relicense portions of *
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* Nmap or grant special permissions to use it in other open source *
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* software. Please contact fyodor@nmap.org with any such requests. *
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* Similarly, we don't incorporate incompatible open source software into *
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* Covered Software without special permission from the copyright holders. *
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* *
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* If you have any questions about the licensing restrictions on using *
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* Nmap in other works, are happy to help. As mentioned above, we also *
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* offer alternative license to integrate Nmap into proprietary *
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* applications and appliances. These contracts have been sold to dozens *
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* of software vendors, and generally include a perpetual license as well *
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* as providing for priority support and updates. They also fund the *
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* continued development of Nmap. Please email sales@nmap.com for further *
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* information. *
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* *
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* If you have received a written license agreement or contract for *
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* Covered Software stating terms other than these, you may choose to use *
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* and redistribute Covered Software under those terms instead of these. *
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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, *
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* and add new features. You are highly encouraged to send your changes *
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* to the dev@nmap.org mailing list for possible incorporation into the *
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* main distribution. By sending these changes to Fyodor or one of the *
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* Insecure.Org development mailing lists, or checking them into the Nmap *
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* source code repository, it is understood (unless you specify otherwise) *
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* that you are offering the Nmap Project (Insecure.Com LLC) the *
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* unlimited, non-exclusive right to reuse, modify, and relicense the *
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* code. Nmap will always be available Open Source, but this is important *
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* because the inability to relicense code has caused devastating problems *
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* for other Free Software projects (such as KDE and NASM). We also *
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* occasionally relicense the code to third parties as discussed above. *
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* If you wish to specify special license conditions of your *
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* contributions, just say so when you send them. *
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* *
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* This program is distributed in the hope that it will be useful, but *
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* WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the Nmap *
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* license file for more details (it's in a COPYING file included with *
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* Nmap, and also available from https://svn.nmap.org/nmap/COPYING) *
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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 "TransportLayerElement.h"
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#include "IPv4Header.h"
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#include "IPv6Header.h"
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/** Computes and returns the Internet checksum.
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* @warning This method requires the object to be linked to either an IPv6Header
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* object or an IPv4Header one, so the caller must ensure that objects are
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* properly linked with calls to setNextElement() like this:
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*
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* IPv6Header ip6;
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* TCPHeader tcp;
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* [...] # Set header fields
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* ip6.setNextElement(&tcp);
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* tcp.setSum();
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*
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* Note that there can be a number of other headers (like IPv6 extension headers)
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* between the transport header and the network one, but all of them need to
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* be linked in order for this method to traverse the list of headers and find
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* the IP source and destination address, required to compute the checksum. So
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* things like the following are OK:
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*
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* IPv6Header ip6;
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* HopByHopHeader hop;
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* RoutingHeader rte;
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* FragmentHeader frg;
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* UDPHeader udp;
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* [...] # Set whatever header fields you need
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* ip6.setNextElement(&hop);
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* hop.setNextElement(&rte);
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* rte.setNextElement(&frg);
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* frg.setNextElement(&udp);
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* udp.setSum(); # setSum() will be able to reach the IPv6Header. */
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u16 TransportLayerElement::compute_checksum(){
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PacketElement *hdr;
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hdr=this->getPrevElement();
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u16 final_sum=0;
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/* Traverse the list of headers backwards until we find an IP header */
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while(hdr!=NULL){
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if (hdr->protocol_id()==HEADER_TYPE_IPv6){
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IPv6Header *v6hdr=(IPv6Header *)hdr;
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struct in6_addr i6src, i6dst;
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memcpy(i6src.s6_addr, v6hdr->getSourceAddress(), 16);
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memcpy(i6dst.s6_addr, v6hdr->getDestinationAddress(), 16);
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u8 *buff=(u8 *)safe_malloc(this->getLen());
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this->dumpToBinaryBuffer(buff, this->getLen());
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final_sum=ipv6_pseudoheader_cksum(&i6src, &i6dst, this->protocol_id(), this->getLen(), buff);
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free(buff);
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return final_sum;
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}else if(hdr->protocol_id()==HEADER_TYPE_IPv4){
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IPv4Header *v4hdr=(IPv4Header *)hdr;
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struct in_addr i4src, i4dst;
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memcpy(&(i4src.s_addr), v4hdr->getSourceAddress(), 4);
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memcpy(&(i4dst.s_addr), v4hdr->getDestinationAddress(), 4);
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u8 *buff=(u8 *)safe_malloc(this->getLen());
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this->dumpToBinaryBuffer(buff, this->getLen());
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final_sum=ipv4_pseudoheader_cksum(&i4src, &i4dst, this->protocol_id(), this->getLen(), buff);
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free(buff);
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return final_sum;
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}else{
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hdr=hdr->getPrevElement();
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}
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}
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return 0;
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} /* End of setSum() */
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