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nmap/libnetutil/HopByHopHeader.cc

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/***************************************************************************
* HopByHopHeader.cc -- The HopByHopHeader Class represents an IPv6 *
* Hop-by-Hop extension header. *
***********************IMPORTANT NMAP LICENSE TERMS************************
* *
* The Nmap Security Scanner is (C) 1996-2016 Insecure.Com LLC ("The Nmap *
* Project"). Nmap is also a registered trademark of the Nmap Project. *
* 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 ("GPL"), BUT ONLY WITH ALL OF THE *
* CLARIFICATIONS AND EXCEPTIONS DESCRIBED HEREIN. 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@nmap.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 "derivative 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 with any software or content covered by this license *
* ("Covered Software"): *
* *
* o Integrates source code from Covered Software. *
* *
* o Reads or includes copyrighted data files, such as Nmap's nmap-os-db *
* or nmap-service-probes. *
* *
* o Is designed specifically to execute Covered Software and parse the *
* results (as opposed to typical shell or execution-menu apps, which will *
* execute anything you tell them to). *
* *
* o Includes Covered Software in a proprietary executable installer. The *
* installers produced by InstallShield are an example of this. Including *
* Nmap with other software in compressed or archival form does not *
* trigger this provision, provided appropriate open source decompression *
* or de-archiving software is widely available for no charge. For the *
* purposes of this license, an installer is considered to include Covered *
* Software even if it actually retrieves a copy of Covered Software from *
* another source during runtime (such as by downloading it from the *
* Internet). *
* *
* o Links (statically or dynamically) to a library which does any of the *
* above. *
* *
* o Executes a helper program, module, or script to do any of the above. *
* *
* This list is not exclusive, but is meant to clarify our interpretation *
* of derived works with some common examples. Other people may interpret *
* the plain GPL differently, so we consider this a special exception to *
* the GPL that we apply to Covered Software. Works which meet any of *
* these conditions must conform to all of the terms of this license, *
* particularly including the GPL Section 3 requirements of providing *
* source code and allowing free redistribution of the work as a whole. *
* *
* As another special exception to the GPL terms, the Nmap Project 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. *
* *
* The Nmap Project has permission to redistribute Npcap, a packet *
* capturing driver and library for the Microsoft Windows platform. *
* Npcap is a separate work with it's own license rather than this Nmap *
* license. Since the Npcap license does not permit redistribution *
* without special permission, our Nmap Windows binary packages which *
* contain Npcap may not be redistributed without special permission. *
* *
* Any redistribution of Covered Software, including any derived works, *
* must obey and carry forward all of the terms of this license, including *
* obeying all GPL rules and restrictions. For example, source code of *
* the whole work must be provided and free redistribution must be *
* allowed. All GPL references to "this License", are to be treated as *
* including the terms and conditions of this license text as well. *
* *
* Because this license imposes special exceptions to the GPL, Covered *
* Work may not be combined (even as part of a larger work) with plain GPL *
* software. The terms, conditions, and exceptions of this license must *
* be included as well. This license is incompatible with some other open *
* source licenses as well. In some cases we can relicense portions of *
* Nmap or grant special permissions to use it in other open source *
* software. Please contact fyodor@nmap.org with any such requests. *
* Similarly, we don't incorporate incompatible open source software into *
* Covered Software without special permission from the copyright holders. *
* *
* If you have any questions about the licensing restrictions on using *
* Nmap in other works, are 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@nmap.com for further *
* information. *
* *
* If you have received a written license agreement or contract for *
* Covered Software stating terms other than these, you may choose to use *
* and redistribute Covered Software under those terms instead of these. *
* *
* 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 send your changes *
* to the dev@nmap.org mailing list 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 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 Nmap *
* license file for more details (it's in a COPYING file included with *
* Nmap, and also available from https://svn.nmap.org/nmap/COPYING) *
* *
***************************************************************************/
/* This code was originally part of the Nping tool. */
#include "HopByHopHeader.h"
#include <assert.h>
/******************************************************************************/
/* 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 || len<HOPBYHOP_MIN_HEADER_LEN){
this->length=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 necessary 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() */
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