/*************************************************************************** * IPv4Header.cc -- The IPv4Header Class represents an IPv4 datagram. It * * contains methods to set any header field. In general, these methods do * * error checkings and byte order conversion. * * * ***********************IMPORTANT NMAP LICENSE TERMS************************ * * * The Nmap Security Scanner is (C) 1996-2012 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, version detection, and the Nmap Scripting Engine. * * * * 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 interpret that term as broadly as copyright law * * allows. For example, 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, as well as other software we distribute under this * * license such as Zenmap, Ncat, and Nping. 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. They also fund the * * continued development of Nmap. 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, or checking them into the Nmap * * source code repository, it is understood (unless you specify otherwise) * * 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 "IPv4Header.h" /******************************************************************************/ /* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */ /******************************************************************************/ IPv4Header::IPv4Header() { this->reset(); } /* End of IPv4Header constructor */ IPv4Header::~IPv4Header() { } /* End of IPv4Header destructor */ /** Sets every attribute to its default value */ void IPv4Header::reset() { memset(&this->h, 0, sizeof(nping_ipv4_hdr_t)); this->ipoptlen=0; this->length=20; /* Initial value 20. This will be incremented if options are used */ this->setVersion(); this->setHeaderLength(); this->setTOS(IPv4_DEFAULT_TOS); this->setIdentification(IPv4_DEFAULT_ID); this->setTTL(IPv4_DEFAULT_TTL); this->setNextProto(IPv4_DEFAULT_PROTO); this->setTotalLength(); } /* End of IPv4Header destructor */ /******************************************************************************/ /* PacketElement:: OVERWRITTEN METHODS */ /******************************************************************************/ /** @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 *IPv4Header::getBufferPointer(){ return (u8*)(&h); } /* End of getBufferPointer() */ /** Stores supplied packet in the internal buffer so the information * can be accessed using the standard get & set methods. * @warning The IPv4Header class is able to hold a maximum of 60 bytes. If the * supplied buffer is longer than that, only the first 60 bytes will be stored * in the internal buffer. * @warning Supplied len MUST be at least 20 bytes (min IP header length). * @return OP_SUCCESS on success and OP_FAILURE in case of error */ int IPv4Header::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=stored_len; memcpy(&(this->h), buf, stored_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 IPv4Header::protocol_id() const { return HEADER_TYPE_IPv4; } /* End of protocol_id() */ /** Performs some VERY BASIC checks that intend to validate the information * stored in the internal buffer, as a valid protocol header. * @warning If the information stored in the object has been set through a * call to storeRecvData(), the object's internal length count may be updated * if the validation is successful. * @return the length, in bytes, of the header, if its found to be valid or * OP_FAILURE (-1) otherwise. */ int IPv4Header::validate(){ if(this->getVersion()!=4) return OP_FAILURE; else if( this->getHeaderLength()<5) return OP_FAILURE; else if( this->getHeaderLength()*4 > this->length) return OP_FAILURE; this->length=this->getHeaderLength()*4; return this->length; } /* 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 IPv4Header::print(FILE *output, int detail) const { static char ipstring[256]; memset(ipstring, 0, 256); struct in_addr addr; int frag_off = 8 * this->getFragOffset() & 8191; /* 2^13 - 1 */; char ipinfo[512] = ""; /* Temp info about IP. */ char fragnfo[64] = ""; /* Temp info about fragmentation. */ fprintf(output, "IPv4["); this->getSourceAddress(&addr); inet_ntop(AF_INET, &addr, ipstring, sizeof(ipstring)); fprintf(output, "%s", ipstring); fprintf(output, " >"); this->getDestinationAddress(&addr); inet_ntop(AF_INET, &addr, ipstring, sizeof(ipstring)); fprintf(output, " %s", ipstring); /* Is this a fragmented packet? is it the last fragment? */ if (frag_off || this->getMF()) { Snprintf(fragnfo, sizeof(fragnfo), " frag offset=%d%s", frag_off, this->getMF() ? "+" : ""); } /* Create a string with information relevant to the specified level of detail */ if( detail == PRINT_DETAIL_LOW ){ Snprintf(ipinfo, sizeof(ipinfo), "ttl=%d id=%d iplen=%d%s%s%s%s", this->getTTL(), this->getIdentification(), this->getTotalLength(), fragnfo, this->getHeaderLength()==5?"":" ipopts={", this->getHeaderLength()?"":format_ip_options(this->h.options , MIN(this->getHeaderLength()*4, this->length-IP_HEADER_LEN)), this->getHeaderLength()?"":"}"); }else if( detail == PRINT_DETAIL_MED ){ Snprintf(ipinfo, sizeof(ipinfo), "ttl=%d id=%d proto=%d csum=0x%04X iplen=%d%s%s%s%s", this->getTTL(), this->getIdentification(), this->getNextProto(), this->getSum(), this->getTotalLength(), fragnfo, this->getHeaderLength()==5?"":" ipopts={", this->getHeaderLength()==5?"":format_ip_options(this->h.options , MIN(this->getHeaderLength()*4, this->length-IP_HEADER_LEN)), this->getHeaderLength()==5?"":"}"); }else if( detail>=PRINT_DETAIL_HIGH ){ Snprintf(ipinfo, sizeof(ipinfo), "ver=%d ihl=%d tos=0x%02x iplen=%d id=%d%s%s%s%s foff=%d%s ttl=%d proto=%d csum=0x%04X%s%s%s", this->getVersion(), this->getHeaderLength(), this->getTOS(), this->getTotalLength(), this->getIdentification(), (this->getRF() ||this->getDF()||this->getMF()) ? " flg=" : "", (this->getRF()) ? "x" : "", (this->getDF() )? "D" : "", (this->getMF() )? "M": "", frag_off, (this->getMF()) ? "+" : "", this->getTTL(), this->getNextProto(), this->getSum(), this->getHeaderLength()==5?"":" ipopts={", this->getHeaderLength()==5?"":format_ip_options(this->h.options , MIN(this->getHeaderLength()*4, this->length-IP_HEADER_LEN)), this->getHeaderLength()==5?"":"}"); } fprintf(output, " %s]", ipinfo); if(this->next!=NULL){ print_separator(output, detail); next->print(output, detail); } return OP_SUCCESS; } /* End of print() */ /******************************************************************************/ /* PROTOCOL-SPECIFIC METHODS */ /******************************************************************************/ int IPv4Header::setVersion(){ h.ip_v = 4; return 4; } /* End of setVersion() */ u8 IPv4Header::getVersion() const { return (u8)h.ip_v; } /* End of getVersion() */ int IPv4Header::setHeaderLength(){ h.ip_hl = 5 + (ipoptlen/4); return OP_SUCCESS; } /* End of setHeaderLength() */ int IPv4Header::setHeaderLength(u8 l){ h.ip_hl = l; return OP_SUCCESS; } /* End of setHeaderLength() */ u8 IPv4Header::getHeaderLength() const { return h.ip_hl; } /* End of getHeaderLength() */ int IPv4Header::setTOS(u8 v){ h.ip_tos = v; return OP_SUCCESS; } /* End of setTOS() */ u8 IPv4Header::getTOS() const { return h.ip_tos; } /* End of getTOS() */ int IPv4Header::setTotalLength(){ int mylen = 4*getHeaderLength(); int otherslen=0; if (next!=NULL) otherslen=next->getLen(); h.ip_len=htons( mylen+otherslen ); return OP_SUCCESS; } /* End of setTotalLength() */ /** @warning Supplied value MUST be in host byte order because it will get * converted by this method using htons() */ int IPv4Header::setTotalLength(u16 l){ h.ip_len = htons(l); return OP_SUCCESS; } /* End of setTotalLength() */ /** @warning Returned value is already in host byte order. */ u16 IPv4Header::getTotalLength() const { return ntohs(h.ip_len); } /* End of getTotalLength() */ /** Sets identification field to a random value */ int IPv4Header::setIdentification(){ h.ip_id=get_random_u16(); return OP_SUCCESS; } /* End of setIdentification() */ /** @warning Supplied value MUST be in host byte order because it will get * converted by this method using htons() */ int IPv4Header::setIdentification(u16 i){ h.ip_id = htons(i); return OP_SUCCESS; } /* End of setIdentification() */ /** @warning Returned value is already in host byte order. */ u16 IPv4Header::getIdentification() const { return ntohs(h.ip_id); } /* End of getIdentification() */ /** Sets fragment offset field to a random value */ int IPv4Header::setFragOffset(){ /* TODO: Should we check here that i<8192 ? */ h.ip_off=get_random_u16(); return OP_SUCCESS; } /* End of setFragOffset() */ /** @warning Supplied value MUST be in host byte order because it will get * converted by this method using htons() */ int IPv4Header::setFragOffset(u16 i){ /* TODO: Should we check here that i<8192 ? */ h.ip_off = htons(i); return OP_SUCCESS; } /* End of setFragOffset() */ /** @warning Returned value is already in host byte order. */ u16 IPv4Header::getFragOffset() const { return ntohs(h.ip_off); } /* End of getFragOffset() */ /** Set RF flag */ int IPv4Header::setRF(){ h.ip_off |= htons(IP_RF); return OP_SUCCESS; } /* End of setRF() */ /** Unset RF flag */ int IPv4Header::unsetRF(){ h.ip_off ^= htons(IP_RF); return OP_SUCCESS; } /* End of unsetRF() */ /** Get RF flag */ bool IPv4Header::getRF() const { return h.ip_off & htons(IP_RF); } /* End of getRF() */ /** Set MF flag */ int IPv4Header::setMF(){ h.ip_off |= htons(IP_MF); return OP_SUCCESS; } /* End of setMF() */ /** Unset MF flag */ int IPv4Header::unsetMF(){ h.ip_off ^= htons(IP_MF); return OP_SUCCESS; } /* End of unsetMF() */ /* Get MF flag */ bool IPv4Header::getMF() const { return h.ip_off & htons(IP_MF); } /* End of getMF() */ /** Set DF flag */ int IPv4Header::setDF(){ h.ip_off |= htons(IP_DF); return OP_SUCCESS; } /* End of setDF() */ /** Unset DF flag */ int IPv4Header::unsetDF(){ h.ip_off ^= htons(IP_DF); return OP_SUCCESS; } /* End of unsetDF() */ /** Get DF flag */ bool IPv4Header::getDF() const { return h.ip_off & htons(IP_DF); } /* End of getDF) */ /** Sets TTL field to a random value */ int IPv4Header::setTTL(){ h.ip_ttl=get_random_u8(); return OP_SUCCESS; } /* End of setTTL() */ /** @warning Supplied value MUST be in host byte order because it will get * converted by this method using htons() */ int IPv4Header::setTTL(u8 t){ h.ip_ttl = t; return OP_SUCCESS; } /* End of setTTL() */ /** @warning Returned value is already in host byte order. */ u8 IPv4Header::getTTL() const { return h.ip_ttl; } /* End of getTTL() */ /** Sets field "next protocol" to the supplied value. * @warning: No error checks are made. Make sure the supplied value * corresponds to an actual IANA number. Check * http://www.iana.org/assignments/protocol-numbers/ for more details. */ int IPv4Header::setNextProto(u8 p){ h.ip_p = p; return OP_SUCCESS; } /* End of setNextProto() */ /** Sets field "next protocol" to the number that corresponds to the supplied * protocol name. Currently onyl TCP, UDP and ICMP are supported. Any * help to extend this functionality would be appreciated. For a list of all * proto names and numbers check: * http://www.iana.org/assignments/protocol-numbers/ */ int IPv4Header::setNextProto(const char *p){ if (p==NULL){ printf("setNextProto(): NULL pointer supplied\n"); return OP_FAILURE; } if( !strcasecmp(p, "TCP") ) h.ip_p=6; /* 6=IANA number for proto TCP */ else if( !strcasecmp(p, "UDP") ) h.ip_p=17; /* 17=IANA number for proto UDP */ else if( !strcasecmp(p, "ICMP") ) h.ip_p=1; /* 1=IANA number for proto ICMP */ else{ printf("setNextProto(): Invalid protocol number\n"); return OP_FAILURE; } return OP_SUCCESS; } /* End of setNextProto() */ /** Returns next protocol number */ u8 IPv4Header::getNextProto() const { return h.ip_p; } /* End of getNextProto() */ u8 IPv4Header::getNextHeader() const { return this->getNextProto(); } /* End of getNextHeader() */ int IPv4Header::setNextHeader(u8 val){ return this->setNextProto(val); } /* End of setNextHeader() */ /** Computes the IPv4 header checksum and sets the ip_sum field to the right * value. */ int IPv4Header::setSum(){ h.ip_sum = 0; /* ip_checksum() comes from libdnet */ ip_checksum((void*)&h, 20 + ipoptlen ); return OP_SUCCESS; } /* End of setSum() */ /** @warning Sum is set to supplied value with NO byte ordering conversion * performed. * @warning If sum is supplied this way, no error checks are made. Caller is * responsible for the correctness of the value. */ int IPv4Header::setSum(u16 s){ h.ip_sum = s; return OP_SUCCESS; } /* End of setSum() */ /** Set the checksum field to a random value */ int IPv4Header::setSumRandom(){ h.ip_sum=get_random_u16(); return OP_SUCCESS; } /* End of setRandomSum() */ /** Returns the value of the checksum field. * @warning The returned value is in NETWORK byte order, no conversion is * performed */ u16 IPv4Header::getSum() const { return h.ip_sum; } /* End of getSum() */ /** Sets destination IP address. * @warning Destination IP must be supplied in NETWORK byte order. Usually * all regular library functions return IPs in network byte order so there * should be no need to worry. */ int IPv4Header::setDestinationAddress(u32 d){ h.ip_dst.s_addr = d; return OP_SUCCESS; } /* End of getDestinationAddress() */ /** Sets destination IP address. * @warning Destination IP must be supplied in NETWORK byte order. Usually * all regular library functions return IPs in network byte order so there * should be no need to worry. */ int IPv4Header::setDestinationAddress(struct in_addr d){ h.ip_dst=d; return OP_SUCCESS; } /* End of getDestinationAddress() */ /** Returns destination IP address. * @warning Returned value is in NETWORK byte order. */ const u8 *IPv4Header::getDestinationAddress() const { return (u8 *)(&h.ip_dst.s_addr); } /* End of getDestinationAddress() */ /** Returns destination IP address. * @warning Returned value is in NETWORK byte order. */ struct in_addr IPv4Header::getDestinationAddress(struct in_addr *result) const { if(result!=NULL) *result=this->h.ip_dst; return h.ip_dst; } /* End of getDestinationAddress() */ /** Sets source IP address. * @warning Destination IP must be supplied in NETWORK byte order. Usually * all regular library functions return IPs in network byte order so there * should be no need to worry. */ int IPv4Header::setSourceAddress(u32 d){ h.ip_src.s_addr = d; return OP_SUCCESS; } /* End of setSourceAddress() */ /** Sets source IP address. * @warning Destination IP must be supplied in NETWORK byte order. Usually * all regular library functions return IPs in network byte order so there * should be no need to worry. */ int IPv4Header::setSourceAddress(struct in_addr d){ h.ip_src=d; return OP_SUCCESS; } /* End of setSourceAddress() */ /** Returns source ip * @warning Returned value is in NETWORK byte order. */ const u8 *IPv4Header::getSourceAddress() const { return (u8 *)(&h.ip_src.s_addr); } /* End of getSourceAddress() */ /** Returns source ip * @warning Returned value is in NETWORK byte order. */ struct in_addr IPv4Header::getSourceAddress(struct in_addr *result) const { if(result!=NULL) *result=this->h.ip_src; return h.ip_src; } /* End of getSourceAddress() */ /** Returns the length of an IPv4 address. */ u16 IPv4Header::getAddressLength() const { return 4; } /* End of getAddressLength()*/ int IPv4Header::setOpts(const char *txt){ int foo=0; int bar=0; int ret=0; u8 buffer[128]; char errstr[256]; if(txt==NULL){ printf("setOpts(): NULL pointer supplied.\n"); return OP_FAILURE; } /* Parse IP options */ if((ret=parse_ip_options(txt, buffer, 128, &foo, &bar, errstr, sizeof(errstr)))==OP_FAILURE){ printf("%s\n", errstr); return OP_FAILURE; }else{ /* Copy options to our IP header */ memcpy(h.options, buffer, ret); this->ipoptlen=ret; this->length += ret; this->setHeaderLength(); } return OP_SUCCESS; } /* End of setOpts() */ const u8 *IPv4Header::getOpts() const { return h.options; } /* End of getOpts() */ const u8 *IPv4Header::getOpts(int *len) const { if(len==NULL) printf("getOpts(): NULL pointer supplied.\n"); *len=ipoptlen; return h.options; } /* End of getOpts() */ int IPv4Header::printOptions() const { char *p=format_ip_options(this->h.options, this->ipoptlen); printf("%s", p); return OP_SUCCESS; } /* End of printOptions() */ const char *IPv4Header::getOptionsString() const { return format_ip_options(this->h.options, this->ipoptlen); } /* End of getOptionsString() */