/*************************************************************************** * HopByHopHeader.cc -- The HopByHopHeader Class represents an IPv6 * * Hop-by-Hop extension header. * ***********************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 "HopByHopHeader.h" #include /******************************************************************************/ /* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */ /******************************************************************************/ HopByHopHeader::HopByHopHeader() { this->reset(); } /* End of HopByHopHeader constructor */ HopByHopHeader::~HopByHopHeader() { } /* End of HopByHopHeader destructor */ /** Sets every attribute to its default value */ void HopByHopHeader::reset(){ memset(&this->h, 0, sizeof(nping_ipv6_ext_hopbyhop_hdr_t)); curr_option=(u8*)this->h.options; this->length=2; this->addOption(EXTOPT_PADN, 4, (const u8*)"\x00\x00\x00\x00"); } /* End of reset() */ /******************************************************************************/ /* 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 *HopByHopHeader::getBufferPointer(){ return (u8*)(&this->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 HopByHopHeader class is able to hold a maximum of * sizeof(nping_icmpv6_hdr_t) bytes. If the supplied buffer is longer than * that, only the first 1508 bytes will be stored in the internal buffer. * @warning Supplied len MUST be at least 8 bytes (min ICMPv6 header length). * @return OP_SUCCESS on success and OP_FAILURE in case of error */ int HopByHopHeader::storeRecvData(const u8 *buf, size_t len){ if(buf==NULL || lenlength=0; return OP_FAILURE; }else{ /* Store the first 4 bytes, so we can access the HdrExtLen field. */ memcpy(&(this->h), buf, 4); /* Check that the HdrExtLen field makes sense: * 1) Check that it carries as many octets as it claims * 2) Check that we don't exceed our internal storage space. */ if( ((unsigned int)(this->h.len+1))*8 > len || (this->h.len+1)*8 > HOPBYHOP_MAX_HEADER_LEN){ this->length=0; return OP_FAILURE; }else{ int mylen=(this->h.len+1)*8; this->reset(); this->length=mylen; memcpy(&(this->h), buf, this->length); return OP_SUCCESS; } } return OP_FAILURE; } /* 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 HopByHopHeader::protocol_id() const { return HEADER_TYPE_IPv6_HOPOPT; } /* 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 HopByHopHeader::validate(){ nping_ipv6_ext_hopbyhop_opt_t *curr_opt=NULL; u8 *curr_pnt=(u8 *)this->h.options; int bytes_left=this->length-2; /* Check the object's length makes sense*/ if(this->length%8!=0 || this->length < HOPBYHOP_MIN_HEADER_LEN || this->length > HOPBYHOP_MAX_HEADER_LEN){ return OP_FAILURE; } /* Check the header's length field. It should match the object's length */ if( (this->h.len+1)*8 != this->length){ return OP_FAILURE; } /* Now validate the TLV-encoded options. */ while(bytes_left>0){ /* Use the opts structure as a template to access current option */ curr_opt=(nping_ipv6_ext_hopbyhop_opt_t *)curr_pnt; /* Let's see what we have. */ switch(curr_opt->type){ /* Pad1 +-+-+-+-+-+-+-+-+ | 0 | +-+-+-+-+-+-+-+-+ */ case EXTOPT_PAD1: curr_pnt++; /* Skip one octet */ bytes_left++; break; /* PadN +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - | 1 | Padding Len | Padding +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - - */ case EXTOPT_PADN: /* Check we have as many octets as the option advertises */ if(bytes_left<2+curr_opt->len) return OP_FAILURE; curr_pnt+=2+curr_opt->len; bytes_left-=2+curr_opt->len; break; /* Jumbo Payload Option (RFC 2675). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Opt Data Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Jumbo Payload Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_JUMBO: /* Jumbo has a fixed length of 4 octets (plus 2). */ if(curr_opt->len!=4) return OP_FAILURE; /* Check if we actually have all the octets */ if(bytes_left<2+4) return OP_FAILURE; curr_pnt+=6; bytes_left-=6; break; /* Tunnel Encapsulation limit (RFC 2473). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | 1 | Tun Encap Lim | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_TUNENCAPLIM: /* This one also has a fixed length. */ if(curr_opt->len!=1) return OP_FAILURE; /* Check if we actually have all the octets */ if(bytes_left<2+1) return OP_FAILURE; curr_pnt+=3; bytes_left-=3; break; /* Router Alert (RFC 2711). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | 2 | Value (2 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_ROUTERALERT: /* Fixed length (two octets)*/ if(curr_opt->len!=2) return OP_FAILURE; /* Check that we actually have all the octets */ if(bytes_left<2+2) return OP_FAILURE; curr_pnt+=4; bytes_left-=4; break; /* Quick-Start (RFC 4782). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option | Length=6 | Func. | Rate | Not Used | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | QS Nonce | R | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */ case EXTOPT_QUICKSTART: /* Fixed length (two octets)*/ if(curr_opt->len!=6) return OP_FAILURE; /* Check that we actually have all the octets */ if(bytes_left<2+6) return OP_FAILURE; curr_pnt+=8; bytes_left-=8; break; /* CALIPSO (RFC 5570). +----------------------------+ | Option Type | Option Length| +-------------+---------------+-------------+--------------+ | CALIPSO Domain of Interpretation | +-------------+---------------+-------------+--------------+ | Cmpt Length | Sens Level | Checksum (CRC-16) | +-------------+---------------+-------------+--------------+ | Compartment Bitmap (Optional; variable length) | +-------------+---------------+-------------+--------------+ */ case EXTOPT_CALIPSO: /* The length of the CALIPSO option is variable because the * Compartment Bitmap is not mandatory. However, the length * must be at least 8. */ if(curr_opt->len<8) return OP_FAILURE; /* Check that we actually have all the octets */ if(bytes_left<2+curr_opt->len) return OP_FAILURE; curr_pnt+=2+curr_opt->len; bytes_left-=2+curr_opt->len; break; /* Home Address (RFC 6275). +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Option Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Home Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+*/ case EXTOPT_HOMEADDR: /* Fixed length of 16 */ if(curr_opt->len!=16) return OP_FAILURE; /* Check if we actually have all the octets */ if(bytes_left<2+16) return OP_FAILURE; curr_pnt+=18; bytes_left-=18; break; /* Option Type Unknown */ default: /* If we don't know the option, we can still try to validate it, * checking if the OptionLength contains something reasonable. */ /* Fixed length of 16 */ if(bytes_left<2+curr_opt->len) return OP_FAILURE; curr_pnt+=2+curr_opt->len; bytes_left-=2+curr_opt->len; break; } } 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 HopByHopHeader::print(FILE *output, int detail) const { fprintf(output, "HopByHop[%d,%d]", this->h.nh, this->h.len); // TODO: @todo : Implement this if(this->next!=NULL){ print_separator(output, detail); next->print(output, detail); } return OP_SUCCESS; } /* End of print() */ /******************************************************************************/ /* PROTOCOL-SPECIFIC METHODS */ /******************************************************************************/ /** Set Next Header field */ int HopByHopHeader::setNextHeader(u8 val){ this->h.nh = val; return OP_SUCCESS; } /* End of setNextHeader() */ /** Returns next header id */ u8 HopByHopHeader::getNextHeader(){ return this->h.nh; } /* End of getNextHeader() */ /* Add TLV encoded option */ int HopByHopHeader::addOption(u8 type, u8 len, const u8 *data){ /* Make sure we don't screw up due to buffer length issues */ if(data==NULL) return OP_FAILURE; if ( (this->length+len+2) > HOPBYHOP_MAX_HEADER_LEN ) /* No space for more */ return OP_FAILURE; /* Store the option */ curr_option[0]=type; curr_option[1]=len; memcpy(curr_option+2, data, len); /* Update internal option offset and object's length */ curr_option+=(len+2); this->length+=(len+2); this->addPadding(); return OP_SUCCESS; } /* End of addOption() */ /* If the current length of the extension header is not a multiple of 8 octets, * this method adds the neccessary padding (either PadN or Pad1 options)*/ int HopByHopHeader::addPadding(){ u8 zeroes[8]={0,0,0,0,0,0,0,0}; int required_octets=8-(this->length%8); /* Make sure we have enough space for the padding. */ if ( (this->length+required_octets) > HOPBYHOP_MAX_HEADER_LEN ) return OP_FAILURE; /* Insert Pad1 or PadN to fill the necessary octets */ if(required_octets>0 && required_octets<8){ if(required_octets==1){ curr_option[0]=EXTOPT_PAD1; curr_option++; this->length++; }else{ this->addOption(EXTOPT_PADN, required_octets-2, zeroes ); } } assert(this->length%8==0); this->h.len=(this->length/8)-1; return OP_SUCCESS; } /* End of addPadding() */