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| -rw-r--r-- | libnetutil/RoutingHeader.cc | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/libnetutil/RoutingHeader.cc b/libnetutil/RoutingHeader.cc new file mode 100644 index 0000000..b978163 --- /dev/null +++ b/libnetutil/RoutingHeader.cc @@ -0,0 +1,313 @@ +/*************************************************************************** + * RoutingHeader.cc -- The RoutingHeader Class represents an IPv6 Routing * + * extension header. * + ***********************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 "RoutingHeader.h" +#include <assert.h> + +/******************************************************************************/ +/* CONTRUCTORS, DESTRUCTORS AND INITIALIZATION METHODS */ +/******************************************************************************/ +RoutingHeader::RoutingHeader() { + this->reset(); +} /* End of RoutingHeader constructor */ + + +RoutingHeader::~RoutingHeader() { + +} /* End of RoutingHeader destructor */ + + +/** Sets every attribute to its default value */ +void RoutingHeader::reset(){ + memset(&this->h, 0, sizeof(nping_ipv6_ext_routing_hdr_t)); + this->length=ROUTING_HEADER_MIN_LEN; + this->curr_addr=(u8 *)this->h.data; +} /* 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 *RoutingHeader::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 RoutingHeader 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 RoutingHeader::storeRecvData(const u8 *buf, size_t len){ + if(buf==NULL || len<ROUTING_HEADER_MIN_LEN){ + this->length=0; + return OP_FAILURE; + }else{ + /* Store the first 4 bytes, so we can access length and routing type */ + memcpy(&(this->h), buf, 4); + + /* Our behaviour is different depending on the routing type. */ + switch(this->h.type){ + + // No checks against ROUTING_HEADER_MAX_LEN because h.len cannot get that large: + // h.len is u8, max value 0xff, so (0xff+1)*8 = 0x800 + // but ROUTING_HEADER_MAX_LEN is 8+256*8 = 0x808 + + /* Routing Type 0 (deprecated by RFC 5095)*/ + case 0: + /* Type 0 has a variable length, but the value of its HdrExtLen + * field must be even (because it must be a multiple of the + * IPv6 address size). We also make sure that the received buffer + * has as many bytes as the HdrExtLen field says it has, and + * that it doesn't exceed the maximum number of octets we + * can store in this object. */ + if(this->h.len%2==1 || ((unsigned int)(this->h.len+1))*8 > len){ + this->length=0; + return OP_FAILURE; + }else{ + int pkt_len=(this->h.len+1)*8; + this->reset(); + this->length=pkt_len; + memcpy(&(this->h), buf, this->length); + return OP_SUCCESS; + } + break; + + /* Routing Type 2 (For IPv6 Mobility. See RFC 6275) */ + case 2: + /* Type 2 has a fixed length. If we have that many octets, store + * them. We'll perform validation later in validate(). */ + if(len<ROUTING_TYPE_2_HEADER_LEN){ + this->length=0; + return OP_FAILURE; + }else{ + this->reset(); + memcpy(&(this->h), buf, ROUTING_TYPE_2_HEADER_LEN); + this->length=ROUTING_TYPE_2_HEADER_LEN; + return OP_SUCCESS; + } + break; + + /* Unknown routing type */ + default: + /* If this is some routing type that we don't know about, we'll have + * to store as much data as the header says it has. Obvioulsy, we + * check that we received as much data as the HdrExtLen advertises, + * and that we don't exceed our own internal limit. */ + if( ((unsigned int)(this->h.len+1))*8 > len){ + this->length=0; + return OP_FAILURE; + }else{ + this->reset(); + this->length=(this->h.len+1)*8; + memcpy(&(this->h), buf, this->length); + return OP_SUCCESS; + } + break; + } + } + 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 RoutingHeader::protocol_id() const { + return HEADER_TYPE_IPv6_ROUTE; +} /* 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 RoutingHeader::validate(){ + + /* Check the object's length makes sense*/ + if(this->length < ROUTING_HEADER_MIN_LEN || this->length%8!=0) { + return OP_FAILURE; + } + + switch(this->h.type){ + /* Routing Type 0 (deprecated by RFC 5095)*/ + case 0: + /* Here we check that: + * 1) The length in HdrExtLen is even. + * 2) The length in HdrExtLen matches the octects stored in this object. + * 3) The length in HdrExtLen does not exceed our internal limit. */ + if(this->h.len%2==1 || (this->h.len+1)*8 != this->length){ + return OP_FAILURE; + } + + /* Also, for Type 0, the value in the SegmentsLeft field should be less + * than or equal to the number of addresses in the packet. We verify + * that using the value of the HDrExtLen field which, divided by two, + * yields the number of addresses in the packet. It certainly doesn't + * make sense for the packet to say there are 5 hops left when we + * have less than 5 IPv6 addresses. We allow it to be less than + * the number of addresses present in the packet because the RFC 2460 + * only talkes about segleft being greater than HDrExtLen/2, not less. */ + if(this->h.segleft > this->h.len/2){ + return OP_FAILURE; + } + break; + + /* Routing Type 2 (For IPv6 Mobility. See RFC 6275) */ + case 2: + /* Check that we have the exact number of octets we expect. */ + if(this->length!= ROUTING_TYPE_2_HEADER_LEN){ + return OP_FAILURE; + } + /* Also check that the HdrExtLen and SegmentsLeft fields have the + * value that RFC 6275 dictates. */ + if(this->h.segleft!=1 || this->h.len!=2){ + return OP_FAILURE; + } + break; + + /* Unknown routing type */ + default: + /* If this is some routing type that we don't know about, we just + * check that the length makes sense because we cannot make assumptions + * about the semantics of other fields. */ + if( this->length!=(this->h.len+1)*8){ + return OP_FAILURE; + } + 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 RoutingHeader::print(FILE *output, int detail) const { + fprintf(output, "Routing[nh=%d len=%d type=%d segleft=%d]", this->h.nh, this->h.len, this->h.type, this->h.segleft); + // 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 RoutingHeader::setNextHeader(u8 val){ + this->h.nh = val; + return OP_SUCCESS; +} /* End of setNextHeader() */ + + +/** Returns next header id */ +u8 RoutingHeader::getNextHeader(){ + return this->h.nh; +} /* End of getNextHeader() */ + + +/** Set routing type */ +int RoutingHeader::setRoutingType(u8 val){ + this->h.type = val; + return OP_SUCCESS; +} /* End of setRoutingType() */ + + +/** Returns the routing type */ +u8 RoutingHeader::getRoutingType(){ + return this->h.type; +} /* End of getRoutingType() */ + + +/** Set number of segments left */ +int RoutingHeader::setSegmentsLeft(u8 val){ + this->h.segleft = val; + return OP_SUCCESS; +} /* End of setSegmentsLeft() */ + + +/** Returns the number of segments left */ +u8 RoutingHeader::getSegmentsLeft(){ + return this->h.segleft; +} /* End of getSegmentsLeft() */ + + +/** Set number of segments left */ +int RoutingHeader::addAddress(struct in6_addr val){ + /* Check we don't exceed max length */ + if((this->length + 16)>ROUTING_HEADER_MAX_LEN) + return OP_FAILURE; + memcpy(this->curr_addr, val.s6_addr, 16); + this->curr_addr+=16; + this->h.len+=2; + this->length+=16; + return OP_SUCCESS; +} /* End of setSegmentsLeft() */ |