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nmap/libnetutil/PacketParser.cc

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/***************************************************************************
* PacketParser.cc -- The PacketParser Class offers methods to parse *
* received network packets. Its main purpose is to facilitate the *
* conversion of raw sequences of bytes into chains of objects of the *
* PacketElement family. *
* *
***********************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 "PacketParser.h"
#include <assert.h>
#define PKTPARSERDEBUG false
PacketParser::PacketParser() {
this->reset();
} /* End of PacketParser constructor */
PacketParser::~PacketParser() {
} /* End of PacketParser destructor */
/** Sets every attribute to its default value- */
void PacketParser::reset() {
} /* End of PacketParser destructor */
const char *PacketParser::header_type2string(int val){
header_type_string_t header_types[]={
{HEADER_TYPE_IPv6_HOPOPT, "IPv6 Hop-by-Hop"},
{HEADER_TYPE_ICMPv4,"ICMPv4"},
{HEADER_TYPE_IGMP,"IGMP"},
{HEADER_TYPE_IPv4,"IPv4"},
{HEADER_TYPE_TCP,"TCP"},
{HEADER_TYPE_EGP,"EGP"},
{HEADER_TYPE_UDP,"UDP"},
{HEADER_TYPE_IPv6,"IPv6"},
{HEADER_TYPE_IPv6_ROUTE,"IPv6-Route"},
{HEADER_TYPE_IPv6_FRAG,"IPv6-Frag"},
{HEADER_TYPE_GRE,"GRE"},
{HEADER_TYPE_ESP,"ESP"},
{HEADER_TYPE_AH,"AH"},
{HEADER_TYPE_ICMPv6,"ICMPv6"},
{HEADER_TYPE_IPv6_NONXT,"IPv6-NoNxt"},
{HEADER_TYPE_IPv6_OPTS,"IPv6-Opts"},
{HEADER_TYPE_EIGRP,"EIGRP"},
{HEADER_TYPE_ETHERNET,"Ethernet"},
{HEADER_TYPE_L2TP,"L2TP"},
{HEADER_TYPE_SCTP,"SCTP"},
{HEADER_TYPE_IPv6_MOBILE,"Mobility Header"},
{HEADER_TYPE_MPLS_IN_IP,"MPLS-in-IP"},
{HEADER_TYPE_ARP,"ARP"},
{HEADER_TYPE_RAW_DATA,"Raw Data"},
{0,NULL}
};
int i=0;
for(i=0; header_types[i].str!=NULL; i++ ){
if((int)header_types[i].type==val)
return header_types[i].str;
}
return NULL;
} /* End of header_type2string() */
#define MAX_HEADERS_IN_PACKET 32
pkt_type_t *PacketParser::parse_packet(const u8 *pkt, size_t pktlen, bool eth_included){
if(PKTPARSERDEBUG)printf("%s(%p, %lu)\n", __func__, pkt, (long unsigned)pktlen);
static pkt_type_t this_packet[MAX_HEADERS_IN_PACKET+1]; /* Packet structure array */
u8 current_header=0; /* Current array position of "this_packet" */
const u8 *curr_pkt=pkt; /* Pointer to current part of the packet */
size_t curr_pktlen=pktlen; /* Remaining packet length */
int ethlen=0, arplen=0; /* Aux length variables: link layer */
int iplen=0,ip6len=0; /* Aux length variables: network layer */
int tcplen=0,udplen=0,icmplen=0; /* Aux length variables: transport layer */
int exthdrlen=0; /* Aux length variables: extension headers */
int next_layer=0; /* Next header type to process */
int expected=0; /* Next protocol expected */
bool finished=false; /* Loop breaking flag */
bool unknown_hdr=false; /* Indicates unknown header found */
IPv4Header ip4;
IPv6Header ip6;
TCPHeader tcp;
UDPHeader udp;
ICMPv4Header icmp4;
ICMPv6Header icmp6;
EthernetHeader eth;
DestOptsHeader ext_dopts;
FragmentHeader ext_frag;
HopByHopHeader ext_hopt;
RoutingHeader ext_routing;
ARPHeader arp;
memset(this_packet, 0, sizeof(this_packet));
/* Decide which layer we have to start from */
if( eth_included ){
next_layer=LINK_LAYER;
expected=HEADER_TYPE_ETHERNET;
}else{
next_layer=NETWORK_LAYER;
}
/* Header processing loop */
while(!finished && curr_pktlen>0 && current_header<MAX_HEADERS_IN_PACKET){
/* Ethernet and ARP headers ***********************************************/
if(next_layer==LINK_LAYER ){
if(PKTPARSERDEBUG)puts("Next Layer=Link");
if(expected==HEADER_TYPE_ETHERNET){
if(PKTPARSERDEBUG)puts("Expected Layer=Ethernet");
if(eth.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE){
unknown_hdr=true;
break;
}
if( (ethlen=eth.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
/* Determine next header type */
switch( eth.getEtherType() ){
case ETHTYPE_IPV4:
expected=HEADER_TYPE_IPv4;
next_layer=NETWORK_LAYER;
break;
case ETHTYPE_IPV6:
expected=HEADER_TYPE_IPv6;
next_layer=NETWORK_LAYER;
break;
case ETHTYPE_ARP:
next_layer=LINK_LAYER;
expected=HEADER_TYPE_ARP;
break;
default:
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
break;
}
this_packet[current_header].length=ethlen;
this_packet[current_header++].type=HEADER_TYPE_ETHERNET;
eth.reset();
curr_pkt+=ethlen;
curr_pktlen-=ethlen;
}else if(expected==HEADER_TYPE_ARP){
if(PKTPARSERDEBUG)puts("Expected Layer=ARP");
if(arp.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE){
unknown_hdr=true;
break;
}
if( (arplen=arp.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
this_packet[current_header].length=arplen;
this_packet[current_header++].type=HEADER_TYPE_ARP;
arp.reset();
curr_pkt+=arplen;
curr_pktlen-=arplen;
if(curr_pktlen>0){
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
}else{
finished=true;
}
}else{
assert(finished==true);
}
/* IPv4 and IPv6 headers **************************************************/
}else if(next_layer==NETWORK_LAYER){
if(PKTPARSERDEBUG)puts("Next Layer=Network");
/* Determine IP version */
if (ip4.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE){
unknown_hdr=true;
break;
}
/* IP version 4 ---------------------------------*/
if(ip4.getVersion()==4){
if( (iplen=ip4.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
/* Determine next header type */
switch(ip4.getNextProto()){
case HEADER_TYPE_ICMPv4:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_ICMPv4;
break;
case HEADER_TYPE_IPv4: /* IP in IP */
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv4;
break;
case HEADER_TYPE_TCP:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_TCP;
break;
case HEADER_TYPE_UDP:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_UDP;
break;
case HEADER_TYPE_IPv6: /* IPv6 in IPv4 */
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv6;
break;
default:
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
break;
}
this_packet[current_header].length=iplen;
this_packet[current_header++].type=HEADER_TYPE_IPv4;
ip4.reset();
curr_pkt+=iplen;
curr_pktlen-=iplen;
/* IP version 6 ---------------------------------*/
}else if(ip4.getVersion()==6){
ip4.reset();
if (ip6.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE){
unknown_hdr=true;
break;
}
if( (ip6len=ip6.validate())==OP_FAILURE ){
unknown_hdr=true;
break;
}
switch( ip6.getNextHeader() ){
case HEADER_TYPE_ICMPv6:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_ICMPv6;
break;
case HEADER_TYPE_IPv4: /* IPv4 in IPv6 */
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv4;
break;
case HEADER_TYPE_TCP:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_TCP;
break;
case HEADER_TYPE_UDP:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_UDP;
break;
case HEADER_TYPE_IPv6: /* IPv6 in IPv6 */
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv6;
break;
case HEADER_TYPE_IPv6_HOPOPT:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_HOPOPT;
break;
case HEADER_TYPE_IPv6_OPTS:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_OPTS;
break;
case HEADER_TYPE_IPv6_ROUTE:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_ROUTE;
break;
case HEADER_TYPE_IPv6_FRAG:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_FRAG;
break;
default:
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
break;
}
this_packet[current_header].length=ip6len;
this_packet[current_header++].type=HEADER_TYPE_IPv6;
ip6.reset();
curr_pkt+=ip6len;
curr_pktlen-=ip6len;
/* Bogus IP version -----------------------------*/
}else{
/* Wrong IP version, treat as raw data. */
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
}
/* TCP, UDP, ICMPv4 and ICMPv6 headers ************************************/
}else if(next_layer==TRANSPORT_LAYER){
if(PKTPARSERDEBUG)puts("Next Layer=Transport");
if(expected==HEADER_TYPE_TCP){
if(PKTPARSERDEBUG)puts("Expected Layer=TCP");
if(tcp.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (tcplen=tcp.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
expected=HEADER_TYPE_RAW_DATA;
this_packet[current_header].length=tcplen;
this_packet[current_header++].type=HEADER_TYPE_TCP;
tcp.reset();
curr_pkt+=tcplen;
curr_pktlen-=tcplen;
next_layer=APPLICATION_LAYER;
}else if(expected==HEADER_TYPE_UDP){
if(PKTPARSERDEBUG)puts("Expected Layer=UDP");
if(udp.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (udplen=udp.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
expected=HEADER_TYPE_RAW_DATA;
this_packet[current_header].length=udplen;
this_packet[current_header++].type=HEADER_TYPE_UDP;
udp.reset();
curr_pkt+=udplen;
curr_pktlen-=udplen;
next_layer=APPLICATION_LAYER;
}else if(expected==HEADER_TYPE_ICMPv4){
if(PKTPARSERDEBUG)puts("Expected Layer=ICMPv4");
if(icmp4.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (icmplen=icmp4.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
switch( icmp4.getType() ){
/* Types that include an IPv4 packet as payload */
case ICMP_UNREACH:
case ICMP_TIMXCEED:
case ICMP_PARAMPROB:
case ICMP_SOURCEQUENCH:
case ICMP_REDIRECT:
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv4;
break;
/* ICMP types that include misc payloads (or no payload) */
default:
expected=HEADER_TYPE_RAW_DATA;
next_layer=APPLICATION_LAYER;
break;
}
this_packet[current_header].length=icmplen;
this_packet[current_header++].type=HEADER_TYPE_ICMPv4;
icmp4.reset();
curr_pkt+=icmplen;
curr_pktlen-=icmplen;
}else if(expected==HEADER_TYPE_ICMPv6){
if(PKTPARSERDEBUG)puts("Expected Layer=ICMPv6");
if(icmp6.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE){
unknown_hdr=true;
break;
}
if( (icmplen=icmp6.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
switch( icmp6.getType() ){
/* Types that include an IPv6 packet as payload */
case ICMPv6_UNREACH:
case ICMPv6_PKTTOOBIG:
case ICMPv6_TIMXCEED:
case ICMPv6_PARAMPROB:
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv6;
break;
/* ICMPv6 types that include misc payloads (or no payload) */
default:
expected=HEADER_TYPE_RAW_DATA;
next_layer=APPLICATION_LAYER;
break;
}
this_packet[current_header].length=icmplen;
this_packet[current_header++].type=HEADER_TYPE_ICMPv6;
icmp6.reset();
curr_pkt+=icmplen;
curr_pktlen-=icmplen;
}else{
/* Wrong application layer protocol, treat as raw data. */
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
}
/* IPv6 Extension Headers */
}else if(next_layer==EXTHEADERS_LAYER){
if(PKTPARSERDEBUG)puts("Next Layer=ExtHdr");
u8 ext_next=0;
/* Hop-by-Hop Options */
if(expected==HEADER_TYPE_IPv6_HOPOPT){
if(PKTPARSERDEBUG)puts("Expected=Hopt");
if(ext_hopt.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (exthdrlen=ext_hopt.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
ext_next=ext_hopt.getNextHeader();
ext_hopt.reset();
/* Routing Header */
}else if(expected==HEADER_TYPE_IPv6_ROUTE){
if(PKTPARSERDEBUG)puts("Expected=Route");
if(ext_routing.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (exthdrlen=ext_routing.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
ext_next=ext_routing.getNextHeader();
ext_routing.reset();
/* Fragmentation Header */
}else if(expected==HEADER_TYPE_IPv6_FRAG){
if(PKTPARSERDEBUG)puts("Expected=Frag");
if(ext_frag.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (exthdrlen=ext_frag.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
ext_next=ext_frag.getNextHeader();
ext_frag.reset();
/* Destination Options Header */
}else if(expected==HEADER_TYPE_IPv6_OPTS){
if(PKTPARSERDEBUG)puts("Expected=Dopts");
if(ext_dopts.storeRecvData(curr_pkt, curr_pktlen)==OP_FAILURE ){
unknown_hdr=true;
break;
}
if( (exthdrlen=ext_dopts.validate())==OP_FAILURE){
unknown_hdr=true;
break;
}
ext_next=ext_dopts.getNextHeader();
ext_dopts.reset();
}else{
/* Should never happen. */
unknown_hdr=true;
break;
}
/* Update the info for this header */
this_packet[current_header].length=exthdrlen;
this_packet[current_header++].type=expected;
curr_pkt+=exthdrlen;
curr_pktlen-=exthdrlen;
/* Lets's see what comes next */
switch(ext_next){
case HEADER_TYPE_ICMPv6:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_ICMPv6;
break;
case HEADER_TYPE_IPv4: /* IPv4 in IPv6 */
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv4;
break;
case HEADER_TYPE_TCP:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_TCP;
break;
case HEADER_TYPE_UDP:
next_layer=TRANSPORT_LAYER;
expected=HEADER_TYPE_UDP;
break;
case HEADER_TYPE_IPv6: /* IPv6 in IPv6 */
next_layer=NETWORK_LAYER;
expected=HEADER_TYPE_IPv6;
break;
case HEADER_TYPE_IPv6_HOPOPT:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_HOPOPT;
break;
case HEADER_TYPE_IPv6_OPTS:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_OPTS;
break;
case HEADER_TYPE_IPv6_ROUTE:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_ROUTE;
break;
case HEADER_TYPE_IPv6_FRAG:
next_layer=EXTHEADERS_LAYER;
expected=HEADER_TYPE_IPv6_FRAG;
break;
default:
next_layer=APPLICATION_LAYER;
expected=HEADER_TYPE_RAW_DATA;
break;
}
/* Miscellaneous payloads *************************************************/
}else{ // next_layer==APPLICATION_LAYER
if(PKTPARSERDEBUG)puts("Next Layer=Application");
if(curr_pktlen>0){
//if(expected==HEADER_TYPE_DNS){
//}else if(expected==HEADER_TYPE_HTTP){
//}... ETC
this_packet[current_header].length=curr_pktlen;
this_packet[current_header++].type=HEADER_TYPE_RAW_DATA;
curr_pktlen=0;
}
finished=true;
}
} /* End of header processing loop */
/* If we couldn't validate some header, treat that header and any remaining
* data, as raw application data. */
if (unknown_hdr==true){
if(curr_pktlen>0){
if(PKTPARSERDEBUG)puts("Unknown layer found. Treating it as raw data.");
this_packet[current_header].length=curr_pktlen;
this_packet[current_header++].type=HEADER_TYPE_RAW_DATA;
}
}
return this_packet;
} /* End of parse_received_packet() */
/* TODO: remove */
int PacketParser::dummy_print_packet_type(const u8 *pkt, size_t pktlen, bool eth_included){
pkt_type_t *packetheaders=PacketParser::parse_packet(pkt, pktlen, eth_included);
for(int i=0; packetheaders[i].length!=0; i++){
printf("%s:", header_type2string(packetheaders[i].type));
}
printf("\n");
return OP_SUCCESS;
} /* End of dummy_print_packet_type() */
int PacketParser::dummy_print_packet(const u8 *pkt, size_t pktlen, bool eth_included){
PacketElement *me=NULL, *aux=NULL;
if( (me=split(pkt, pktlen, eth_included))==NULL )
return OP_FAILURE;
else{
me->print(stdout, PRINT_DETAIL_HIGH);
printf("\n");
}
/* Free the structs */
while(me!=NULL){
aux=me->getNextElement();
delete me;
me=aux;
}
return OP_SUCCESS;
} /* End of dummy_print_packet() */
/** For a given packet, this method determines where the application layer data
* begins. It returs a positive offset if any application data was found, zero
* if the packet did not contain application data and a negative integer in
* case of error. */
int PacketParser::payload_offset(const u8 *pkt, size_t pktlen, bool link_included){
PacketElement *me=NULL, *aux=NULL;
size_t offset=pktlen; /* Initially, point to the end of the packet. */
/* Safe checks*/
if(pkt==NULL || pktlen<=0)
return -1;
dummy_print_packet_type(pkt, pktlen, link_included);
/* Split the packet into separate protocol headers */
if( (me=split(pkt, pktlen, link_included))==NULL )
return -2;
else{
aux=me;
}
/* Find if there is application data and where it begins */
while(me!=NULL){
/* When we find application data, we compute the offset by substacting the
length of the application data from the packet's total length */
if(me->protocol_id()==HEADER_TYPE_RAW_DATA){
offset=pktlen-me->getLen();
break;
me=me->getNextElement();
}else{
me=me->getNextElement();
}
}
/* Free the structs */
me=aux;
while(me!=NULL){
aux=me->getNextElement();
delete me;
me=aux;
}
/* Return 0 if we didn't find any application data */
if(offset==pktlen){
return 0;
}else{
return offset;
}
} /* End of payload_offset() */
PacketElement *PacketParser::split(const u8 *pkt, size_t pktlen){
return split(pkt, pktlen, false);
} /* End of split() */
PacketElement *PacketParser::split(const u8 *pkt, size_t pktlen, bool eth_included){
pkt_type_t *packetheaders=NULL;
const u8 *curr_pkt=pkt;
PacketElement *first=NULL;
PacketElement *last=NULL;
IPv4Header *ip4=NULL;
IPv6Header *ip6=NULL;
DestOptsHeader *ext_dopts=NULL;
FragmentHeader *ext_frag=NULL;
HopByHopHeader *ext_hopt=NULL;
RoutingHeader *ext_routing=NULL;
TCPHeader *tcp=NULL;
UDPHeader *udp=NULL;
ICMPv4Header *icmp4=NULL;
ICMPv6Header *icmp6=NULL;
EthernetHeader *eth=NULL;
ARPHeader *arp=NULL;
RawData *raw=NULL;
/* Analyze the packet. This returns a list of header types and lengths */
if((packetheaders=PacketParser::parse_packet(pkt, pktlen, eth_included))==NULL)
return NULL;
/* Store each header in its own PacketHeader object type */
for(int i=0; packetheaders[i].length!=0; i++){
switch(packetheaders[i].type){
case HEADER_TYPE_ETHERNET:
eth=new EthernetHeader();
eth->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=eth;
}else{
last->setNextElement(eth);
}
last=eth;
break;
case HEADER_TYPE_ARP:
arp=new ARPHeader();
arp->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=arp;
}else{
last->setNextElement(arp);
}
last=arp;
break;
case HEADER_TYPE_IPv4:
ip4=new IPv4Header();
ip4->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=ip4;
}else{
last->setNextElement(ip4);
}
last=ip4;
break;
case HEADER_TYPE_IPv6:
ip6=new IPv6Header();
ip6->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=ip6;
}else{
last->setNextElement(ip6);
}
last=ip6;
break;
case HEADER_TYPE_TCP:
tcp=new TCPHeader();
tcp->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=tcp;
}else{
last->setNextElement(tcp);
}
last=tcp;
break;
case HEADER_TYPE_UDP:
udp=new UDPHeader();
udp->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=udp;
}else{
last->setNextElement(udp);
}
last=udp;
break;
case HEADER_TYPE_ICMPv4:
icmp4=new ICMPv4Header();
icmp4->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=icmp4;
}else{
last->setNextElement(icmp4);
}
last=icmp4;
break;
case HEADER_TYPE_ICMPv6:
icmp6=new ICMPv6Header();
icmp6->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=icmp6;
}else{
last->setNextElement(icmp6);
}
last=icmp6;
break;
case HEADER_TYPE_IPv6_HOPOPT:
ext_hopt=new HopByHopHeader();
ext_hopt->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=ext_hopt;
}else{
last->setNextElement(ext_hopt);
}
last=ext_hopt;
break;
case HEADER_TYPE_IPv6_ROUTE:
ext_routing=new RoutingHeader();
ext_routing->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=ext_routing;
}else{
last->setNextElement(ext_routing);
}
last=ext_routing;
break;
case HEADER_TYPE_IPv6_FRAG:
ext_frag=new FragmentHeader();
ext_frag->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=ext_frag;
}else{
last->setNextElement(ext_frag);
}
last=ext_frag;
break;
case HEADER_TYPE_IPv6_OPTS:
ext_dopts=new DestOptsHeader();
ext_dopts->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=ext_dopts;
}else{
last->setNextElement(ext_dopts);
}
last=ext_dopts;
break;
case HEADER_TYPE_RAW_DATA:
default:
raw=new RawData();
raw->storeRecvData(curr_pkt, packetheaders[i].length);
if(first==NULL){
first=raw;
}else{
last->setNextElement(raw);
}
last=raw;
break;
}
curr_pkt+=packetheaders[i].length;
}
return first;
} /* End of split() */
/* This method frees a chain of PacketElement objects. Note that objects in
* the chain are freed by calling "delete" on them, so only those instances
* that have been obtained through a call to "new" should be passed to this
* method. Chains returned by PacketParser::split() are safe to use with this.*/
int PacketParser::freePacketChain(PacketElement *first){
PacketElement *curr=first;
PacketElement *next=NULL;
while(curr!=NULL){
next=curr->getNextElement();
delete curr;
curr=next;
}
return OP_SUCCESS;
} /* End of freePacketChain() */
/* This method is for debugging purposes only. It tests the packet parser and
* the PacketElement class family. Basically it checks that the supplied
* chain of PacketElements can be serialized and de-serialized correctly.
* Returns NULL on success or an error string in case of failure. */
const char *PacketParser::test_packet_parser(PacketElement *test_pkt){
const char *errmsg=NULL;
PacketElement *parsed_pkt=NULL;
PacketElement *orig_pkt=NULL;
PacketElement *new_pkt=NULL;
u8 *mypktbuff2=NULL;
u8 *mypktbuff=NULL;
if(test_pkt==NULL){
errmsg="NULL pointer supplied";
goto end;
}
/* Generate a serialized version of the packet */
mypktbuff=(u8 *)safe_malloc(test_pkt->getLen());
test_pkt->dumpToBinaryBuffer(mypktbuff, test_pkt->getLen());
/* Generate a chain of PacketElement objects from the serialized version. */
parsed_pkt=PacketParser::split(mypktbuff, test_pkt->getLen());
if(parsed_pkt==NULL){
errmsg="PacketParser::split() returned NULL";
goto end;
}
if(parsed_pkt->getLen()!=test_pkt->getLen()){
errmsg="Packets have different lengths";
goto end;
}
/* Generate a serialized version of the new chain */
mypktbuff2=(u8 *)safe_malloc(parsed_pkt->getLen());
parsed_pkt->dumpToBinaryBuffer(mypktbuff2, parsed_pkt->getLen());
/* Make sure both packets produce the exact same binary buffer */
if(memcmp(mypktbuff, mypktbuff2, parsed_pkt->getLen())!=0){
errmsg="The two packets do not result in the same binary buffer";
goto end;
}
/* Now let's check that both chains have the same number and type of
* PacketElements. */
orig_pkt=test_pkt;
new_pkt=parsed_pkt;
while(orig_pkt!=NULL && new_pkt!=NULL){
if(orig_pkt->protocol_id() != new_pkt->protocol_id() ){
errmsg="Protocol IDs do not match";
goto end;
}
orig_pkt=orig_pkt->getNextElement();
new_pkt=new_pkt->getNextElement();
}
if(orig_pkt!=NULL || new_pkt!=NULL){
errmsg="The two packets do not have the same number of chained elements.";
goto end;
}
end:
/* Free our allocations */
if(mypktbuff!=NULL)
free(mypktbuff);
if(mypktbuff2!=NULL)
free(mypktbuff2);
if(parsed_pkt!=NULL)
PacketParser::freePacketChain(parsed_pkt);
/* If everything went well, errmsg should still be NULL. Otherwise it
* should point to an error message.*/
return errmsg;
}
/* Returns true if the supplied "rcvd" packet is a response to the "sent" packet.
* This method currently handles IPv4, IPv6, ICMPv4, ICMPv6, TCP and UDP. Here
* some examples of what can be matched using it:
*
* Probe: TCP SYN -> Response TCP SYN|ACK
* Probe: TCP SYN -> Response TCP RST|ACK
* Probe: UDP:53 -> Response UDP from port 53.
* Probe ICMP Echo -> Response ICMP Echo reply
* Probe ICMPv6 Neighbor Solicitation -> Response ICMPv6 Neighbor Advert
* Probe Malformed IPv6 -> Response ICMPv6 Parameter Problem
* Probe MLDv1 Query -> Response MLDv1 Report
* Probe ICMP Timestamp request -> Response ICMP timestamp response
* etc...
*
* Note that ICMP error messages are matched against sent probes (e.g: an ICMP
* Parameter Problem generated as a result of an invalid TCP segment is matched
* positively with the original TCP segment). Therefore, the caller must ensure
* that the received packet is what it expects before using it (e.g: the packet
* is an actual TCP packet, not an ICMP error).
*
* Warning: this method assumes that the probes you send are reasonably
* different from each other. Don't expect a 100% accuracy if you send a bunch
* of TCP segments with the same source and destination port numbers, or a
* bunch of ICMP messages with the same identifier and sequence number. */
bool PacketParser::is_response(PacketElement *sent, PacketElement *rcvd){
if(PKTPARSERDEBUG)printf("%s(): called\n", __func__);
if(sent==NULL || rcvd==NULL)
return false;
/* If any of the packets is encapsulated in an Ethernet frame, strip the
* link layer header before proceeding with the matching process. */
if(rcvd->protocol_id()==HEADER_TYPE_ETHERNET)
if( (rcvd=rcvd->getNextElement())==NULL)
return false;
if(sent->protocol_id()==HEADER_TYPE_ETHERNET)
if( (sent=sent->getNextElement())==NULL)
return false;
/* Make sure both packets have the same network layer and that it is IP */
if(rcvd->protocol_id()!=sent->protocol_id())
return false;
if(rcvd->protocol_id()!=HEADER_TYPE_IPv6 && rcvd->protocol_id()!=HEADER_TYPE_IPv4)
return false;
if(PKTPARSERDEBUG)printf("%s(): Both packets use IP.\n", __func__);
/* Handle the network layer with a more specific class */
NetworkLayerElement *rcvd_ip=(NetworkLayerElement *)rcvd;
NetworkLayerElement *sent_ip=(NetworkLayerElement *)sent;
/* Ensure the packet comes from the host we sent the probe to */
if( memcmp(rcvd_ip->getSourceAddress(), sent_ip->getDestinationAddress(), rcvd_ip->getAddressLength())!=0 )
return false;
/* Ensure the received packet is destined to us */
if( memcmp(rcvd_ip->getDestinationAddress(), sent_ip->getSourceAddress(), rcvd_ip->getAddressLength())!=0 )
return false;
if(PKTPARSERDEBUG)printf("%s(): Src and Dst addresses make sense.\n", __func__);
/* Skip layers until we find ICMP or a transport protocol */
PacketElement *rcvd_layer4=rcvd_ip->getNextElement();
PacketElement *sent_layer4=sent_ip->getNextElement();
while(rcvd_layer4!=NULL){
if(rcvd_layer4->protocol_id()==HEADER_TYPE_UDP || rcvd_layer4->protocol_id()==HEADER_TYPE_TCP ||
rcvd_layer4->protocol_id()==HEADER_TYPE_ICMPv4 || rcvd_layer4->protocol_id()==HEADER_TYPE_ICMPv6 ){
break;
}else{
rcvd_layer4=rcvd_layer4->getNextElement();
}
}
while(sent_layer4!=NULL){
if(sent_layer4->protocol_id()==HEADER_TYPE_UDP || sent_layer4->protocol_id()==HEADER_TYPE_TCP ||
sent_layer4->protocol_id()==HEADER_TYPE_ICMPv4 || sent_layer4->protocol_id()==HEADER_TYPE_ICMPv6 ){
break;
}else{
sent_layer4=sent_layer4->getNextElement();
}
}
if(rcvd_layer4==NULL || sent_layer4==NULL)
return false;
if(PKTPARSERDEBUG)printf("%s(): Layer 4 found for both packets.\n", __func__);
/* If we get here it means that both packets have a proper layer4 protocol
* header. Now we have to check which type are they and see if a probe-response
* relation can be established. */
if(sent_layer4->protocol_id()==HEADER_TYPE_ICMPv6 || sent_layer4->protocol_id()==HEADER_TYPE_ICMPv4){
if(PKTPARSERDEBUG)printf("%s(): Sent packet is ICMP.\n", __func__);
/* Make sure received packet is ICMP (we only expect ICMP responses for
* ICMP probes) */
if(rcvd_layer4->protocol_id()!=HEADER_TYPE_ICMPv6 && rcvd_layer4->protocol_id()!=HEADER_TYPE_ICMPv4 )
return false;
/* Make sure both packets have the same ICMP version */
if(sent_layer4->protocol_id()!=rcvd_layer4->protocol_id())
return false;
if(PKTPARSERDEBUG)printf("%s(): Received packet is ICMP too.\n", __func__);
/* Check if the received ICMP is an error message. We don't care which kind
* of error message it is. The only important thing is that error messages
* contain a copy of the original datagram, and that's what we want to
* match against the sent probe. */
if( ((ICMPHeader *)rcvd_layer4)->isError() ){
NetworkLayerElement *iperror=(NetworkLayerElement *)rcvd_layer4->getNextElement();
if(PKTPARSERDEBUG)printf("%s(): Received ICMP is an error message.\n", __func__);
/* ICMP error message must contain the original datagram */
if(iperror==NULL)
return false;
/* The first header must be IP */
if(iperror->protocol_id()!=HEADER_TYPE_IPv6 && iperror->protocol_id()!=HEADER_TYPE_IPv4)
return false;
/* The IP version must match the probe's */
if(iperror->protocol_id()!=sent_ip->protocol_id())
return false;
/* Source and destination addresses must match the probe's */
if( memcmp(iperror->getSourceAddress(), sent_ip->getSourceAddress(), iperror->getAddressLength())!=0 )
return false;
if( memcmp(iperror->getDestinationAddress(), sent_ip->getDestinationAddress(), iperror->getAddressLength())!=0 )
return false;
/* So far we've verified that the ICMP error contains an IP datagram that matches
* what we sent. Now, let's find the upper layer ICMP header (skip extension
* headers until we find ICMP) */
ICMPHeader *inner_icmp=(ICMPHeader *)iperror->getNextElement();
while(inner_icmp!=NULL){
if(inner_icmp->protocol_id()==HEADER_TYPE_ICMPv4 || inner_icmp->protocol_id()==HEADER_TYPE_ICMPv6 ){
break;
}else{
inner_icmp=(ICMPHeader *)inner_icmp->getNextElement();
}
}
if(inner_icmp==NULL)
return false;
/* If we get here it means that we've found an ICMP header inside the
* ICMP error message that we received. First of all, check that the
* ICMP version matches what we sent. */
if(sent_layer4->protocol_id() != inner_icmp->protocol_id())
return false;
/* Make sure ICMP type and code match */
if( ((ICMPHeader*)sent_layer4)->getType() != inner_icmp->getType() )
return false;
if( ((ICMPHeader*)sent_layer4)->getCode() != inner_icmp->getCode() )
return false;
/* Now go into a bit of detail and try to determine if both headers
* are equal, comparing the values of specific fields. */
if(sent_layer4->protocol_id()==HEADER_TYPE_ICMPv6){
ICMPv6Header *sent_icmp6=(ICMPv6Header *)sent_layer4;
ICMPv6Header *inner_icmp6=(ICMPv6Header *)inner_icmp;
switch(sent_icmp6->getType()){
case ICMPv6_UNREACH:
case ICMPv6_TIMXCEED :
/* For these we cannot guarantee that the received ICMPv6 error
* packet included data beyond the inner ICMPv6 header, so we just
* assume that they are a match to the sent probe. (We shouldn't
* really be sending ICMPv6 error messages and expect ICMPv6 error
* responses that contain our ICMv6P error messages, should we?
* Well, even if we do, there is a good chance we are able to match
* those responses with the original probe) */
break;
case ICMPv6_PKTTOOBIG:
if(sent_icmp6->getMTU() != inner_icmp6->getMTU())
return false;
break;
case ICMPv6_PARAMPROB:
if(sent_icmp6->getPointer() != inner_icmp6->getPointer())
return false;
break;
case ICMPv6_ECHO:
case ICMPv6_ECHOREPLY:
if(sent_icmp6->getIdentifier() != inner_icmp6->getIdentifier())
return false;
if(sent_icmp6->getSequence() != inner_icmp6->getSequence())
return false;
break;
case ICMPv6_ROUTERSOLICIT:
/* Here we do not have much to compare, so we just test that
* the reserved field contains the same value, usually zero. */
if(sent_icmp6->getReserved()!=inner_icmp6->getReserved())
return false;
break;
case ICMPv6_ROUTERADVERT:
if(sent_icmp6->getCurrentHopLimit() != inner_icmp6->getCurrentHopLimit() )
return false;
if(sent_icmp6->getRouterLifetime() != inner_icmp6->getRouterLifetime() )
return false;
if(sent_icmp6->getReachableTime() != inner_icmp6->getReachableTime() )
return false;
if(sent_icmp6->getRetransmissionTimer() != inner_icmp6->getRetransmissionTimer() )
return false;
break;
case ICMPv6_REDIRECT:
if( memcmp(sent_icmp6->getTargetAddress().s6_addr, inner_icmp6->getTargetAddress().s6_addr, 16) !=0 )
return false;
if( memcmp(sent_icmp6->getDestinationAddress().s6_addr, inner_icmp6->getDestinationAddress().s6_addr, 16) !=0 )
return false;
break;
case ICMPv6_NGHBRSOLICIT:
case ICMPv6_NGHBRADVERT:
if( memcmp(sent_icmp6->getTargetAddress().s6_addr, inner_icmp6->getTargetAddress().s6_addr, 16) !=0 )
return false;
break;
case ICMPv6_RTRRENUM:
if(sent_icmp6->getSequence() != inner_icmp6->getSequence() )
return false;
if(sent_icmp6->getSegmentNumber() != inner_icmp6->getSegmentNumber() )
return false;
if(sent_icmp6->getMaxDelay() != inner_icmp6->getMaxDelay() )
return false;
if(sent_icmp6->getFlags() != inner_icmp6->getFlags() )
return false;
break;
case ICMPv6_NODEINFOQUERY:
case ICMPv6_NODEINFORESP:
if(sent_icmp6->getNodeInfoFlags() != inner_icmp6->getNodeInfoFlags() )
return false;
if( memcmp(sent_icmp6->getNonce(), inner_icmp6->getNonce(), NI_NONCE_LEN)!=0 )
return false;
if(sent_icmp6->getQtype() != inner_icmp6->getQtype() )
return false;
break;
case ICMPv6_GRPMEMBQUERY:
case ICMPv6_GRPMEMBREP:
case ICMPv6_GRPMEMBRED:
case ICMPv6_INVNGHBRSOLICIT:
case ICMPv6_INVNGHBRADVERT:
case ICMPv6_MLDV2:
case ICMPv6_AGENTDISCOVREQ:
case ICMPv6_AGENTDISCOVREPLY:
case ICMPv6_MOBPREFIXSOLICIT:
case ICMPv6_MOBPREFIXADVERT:
case ICMPv6_CERTPATHSOLICIT:
case ICMPv6_CERTPATHADVERT:
case ICMPv6_EXPMOBILITY:
case ICMPv6_MRDADVERT:
case ICMPv6_MRDSOLICIT:
case ICMPv6_MRDTERMINATE:
case ICMPv6_FMIPV6:
/* All these types are not currently implemented but since the
* sent_icmp.getType() has returned such type, we assume
* that there is a match (don't return false here). */
break;
default:
/* Do not match ICMPv6 types we don't know about */
return false;
break;
}
}else if(sent_layer4->protocol_id()==HEADER_TYPE_ICMPv4){
ICMPv4Header *sent_icmp4=(ICMPv4Header *)sent_layer4;
ICMPv4Header *inner_icmp4=(ICMPv4Header *)inner_icmp;
switch(sent_icmp4->getType()){
case ICMP_ECHOREPLY:
case ICMP_ECHO:
case ICMP_TSTAMP:
case ICMP_TSTAMPREPLY:
case ICMP_INFO:
case ICMP_INFOREPLY:
case ICMP_MASK:
case ICMP_MASKREPLY:
case ICMP_DOMAINNAME:
case ICMP_DOMAINNAMEREPLY:
/* Check the message identifier and sequence number */
if(sent_icmp4->getIdentifier() != inner_icmp4->getIdentifier())
return false;
if(sent_icmp4->getSequence() != inner_icmp4->getSequence())
return false;
break;
case ICMP_ROUTERADVERT:
/* Check only the main fields, no need to parse the whole list
* of addresses (maybe we didn't even get enough octets to
* check that). */
if(sent_icmp4->getNumAddresses() != inner_icmp4->getNumAddresses() )
return false;
if(sent_icmp4->getAddrEntrySize() != inner_icmp4->getAddrEntrySize())
return false;
if(sent_icmp4->getLifetime() != inner_icmp4->getLifetime() )
return false;
break;
case ICMP_ROUTERSOLICIT:
/* Here we do not have much to compare, so we just test that
* the reserved field contains the same value, usually zero. */
if(sent_icmp4->getReserved()!=inner_icmp4->getReserved())
return false;
break;
case ICMP_UNREACH:
case ICMP_SOURCEQUENCH:
case ICMP_TIMXCEED:
/* For these we cannot guarantee that the received ICMP error
* packet included data beyond the inner ICMP header, so we just
* assume that they are a match to the sent probe. (We shouldn't
* really be sending ICMP error messages and expect ICMP error
* responses that contain our ICMP error messages, should we?
* Well, even if we do, there is a good chance we are able to match
* those responses with the original probe) */
break;
case ICMP_REDIRECT:
if(sent_icmp4->getGatewayAddress().s_addr != inner_icmp4->getGatewayAddress().s_addr)
return false;
break;
case ICMP_PARAMPROB:
if(sent_icmp4->getParameterPointer() != inner_icmp4->getParameterPointer())
return false;
break;
case ICMP_TRACEROUTE:
if(sent_icmp4->getIDNumber() != inner_icmp4->getIDNumber())
return false;
if(sent_icmp4->getOutboundHopCount() != inner_icmp4->getOutboundHopCount())
return false;
if(sent_icmp4->getOutputLinkSpeed() != inner_icmp4->getOutputLinkSpeed() )
return false;
if(sent_icmp4->getOutputLinkMTU() != inner_icmp4->getOutputLinkMTU() )
return false;
break;
case ICMP_SECURITYFAILURES:
/* Check the pointer and the reserved field */
if(sent_icmp4->getSecurityPointer() != inner_icmp4->getSecurityPointer())
return false;
if(sent_icmp4->getReserved() != inner_icmp4->getReserved())
return false;
break;
default:
/* Do not match ICMP types we don't know about */
return false;
break;
}
}else{
return false; // Should never happen, though.
}
}else{ /* Received ICMP is informational. */
if(PKTPARSERDEBUG)printf("%s(): Received ICMP is an informational message.\n", __func__);
/* If we get here it means that we received an informational ICMPv6
* message. So now we have to check if the received message is the
* expected reply to the probe we sent (like an Echo reply for an Echo
* request, etc). */
if(sent_layer4->protocol_id()==HEADER_TYPE_ICMPv6 && rcvd_layer4->protocol_id()==HEADER_TYPE_ICMPv6){
ICMPv6Header *sent_icmp6=(ICMPv6Header *)sent_layer4;
ICMPv6Header *rcvd_icmp6=(ICMPv6Header *)rcvd_layer4;
switch( sent_icmp6->getType() ){
case ICMPv6_UNREACH:
case ICMPv6_TIMXCEED :
case ICMPv6_PKTTOOBIG:
case ICMPv6_PARAMPROB:
/* This should never happen. If we got here, the received type
* should be of an informational message, not an error message. */
printf("Error in isResponse()\n");
return false;
break;
case ICMPv6_ECHO:
/* For Echo request, we expect echo replies */
if(rcvd_icmp6->getType()!=ICMPv6_ECHOREPLY)
return false;
/* And we expect the ID and sequence number of the reply to
* match the ID and seq of the request. */
if(sent_icmp6->getIdentifier() != rcvd_icmp6->getIdentifier())
return false;
if(sent_icmp6->getSequence() != rcvd_icmp6->getSequence())
return false;
break;
case ICMPv6_ECHOREPLY:
/* We don't expect replies to Echo replies */
return false;
break;
case ICMPv6_ROUTERSOLICIT:
/* For Router solicitations, we expect Router advertisements.
* We only check if the received ICMP is a router advert because
* there is nothing else that can be used to match the solicitation
* with the response. */
if(rcvd_icmp6->getType()!=ICMPv6_ROUTERADVERT)
return false;
break;
case ICMPv6_ROUTERADVERT:
/* We don't expect replies to router advertisements */
return false;
break;
case ICMPv6_REDIRECT:
/* We don't expect replies to Redirect messages */
return false;
break;
case ICMPv6_NGHBRSOLICIT:
if(PKTPARSERDEBUG)printf("%s(): Sent ICMP is an ICMPv6 Neighbor Solicitation.\n", __func__);
/* For Neighbor solicitations, we expect Neighbor advertisements
* with the "S" flag set (solicited flag) and the same address
* in the "TargetAddress" field. */
if(rcvd_icmp6->getType()!=ICMPv6_NGHBRADVERT)
return false;
if(PKTPARSERDEBUG)printf("%s(): Received ICMP is an ICMPv6 Neighbor Advertisement.\n", __func__);
if( !(rcvd_icmp6->getFlags() & 0x40) )
return false;
if( memcmp(sent_icmp6->getTargetAddress().s6_addr, rcvd_icmp6->getTargetAddress().s6_addr, 16) !=0 )
return false;
break;
case ICMPv6_NGHBRADVERT:
/* We don't expect replies to Neighbor advertisements */
return false;
break;
case ICMPv6_NODEINFOQUERY:
/* For Node Information Queries we expect Node Information
* responses with the same Nonce value that we used in the query. */
if(rcvd_icmp6->getType()!=ICMPv6_NODEINFORESP)
return false;
if( memcmp(sent_icmp6->getNonce(), rcvd_icmp6->getNonce(), NI_NONCE_LEN)!=0 )
return false;
break;
case ICMPv6_NODEINFORESP:
/* Obviously, we do not expect responses to a response */
return false;
break;
case ICMPv6_INVNGHBRSOLICIT:
/* For Inverse Neighbor Discovery Solicitations we expect
* advertisements in response. We don't do any additional
* validation since any advert can be considered a response
* to the solicitation. */
if(rcvd_icmp6->getType()!=ICMPv6_INVNGHBRADVERT)
return false;
break;
case ICMPv6_INVNGHBRADVERT:
/* We don't expect responses to advertisements */
return false;
break;
case ICMPv6_RTRRENUM:
/* We don't expect specific responses to router renumbering
* messages. */
return false;
break;
case ICMPv6_GRPMEMBQUERY:
/* For Multicast Listener Discovery (MLD) queries, we expect
* either MLD Responses or MLD Done messages. We can't handle MLDv2
* yet, so we don't match it. TODO: Implement support for MLDv2 */
if(rcvd_icmp6->getType()!=ICMPv6_GRPMEMBREP && rcvd_icmp6->getType()!=ICMPv6_GRPMEMBRED)
return false;
/* Now we have two possibilities:
* a) The query is a "General Query" where the multicast address
* is set to zero.
* b) The query is a "Multicast-Address-Specific Query", where
* the multicast address field is set to an actual multicast
* address.
* In the first case, we match any query response to the request,
* as we don't have a multicast address to compare. In the second
* case, we verify that the target mcast address of the query
* matches the one in the response. */
struct in6_addr zeroaddr;
memset(&zeroaddr, 0, sizeof(struct in6_addr));
if( memcmp( sent_icmp6->getMulticastAddress().s6_addr, zeroaddr.s6_addr, 16) != 0 ){ /* Case B: */
if (memcmp( sent_icmp6->getMulticastAddress().s6_addr, rcvd_icmp6->getMulticastAddress().s6_addr, 16)!=0 )
return false;
}
break;
case ICMPv6_GRPMEMBREP:
case ICMPv6_GRPMEMBRED:
/* We don't expect responses to MLD reports */
return false;
break;
case ICMPv6_MLDV2:
case ICMPv6_AGENTDISCOVREQ:
case ICMPv6_AGENTDISCOVREPLY:
case ICMPv6_MOBPREFIXSOLICIT:
case ICMPv6_MOBPREFIXADVERT:
case ICMPv6_CERTPATHSOLICIT:
case ICMPv6_CERTPATHADVERT:
case ICMPv6_EXPMOBILITY:
case ICMPv6_MRDADVERT:
case ICMPv6_MRDSOLICIT:
case ICMPv6_MRDTERMINATE:
case ICMPv6_FMIPV6:
default:
/* Do not match ICMPv6 types we don't implement or know about *
* TODO: Implement these ICMPv6 types. */
return false;
break;
}
}else if(sent_layer4->protocol_id()==HEADER_TYPE_ICMPv4 && rcvd_layer4->protocol_id()==HEADER_TYPE_ICMPv4){
ICMPv4Header *sent_icmp4=(ICMPv4Header *)sent_layer4;
ICMPv4Header *rcvd_icmp4=(ICMPv4Header *)rcvd_layer4;
switch( sent_icmp4->getType() ){
case ICMP_ECHOREPLY:
/* We don't expect replies to Echo replies. */
return false;
break;
case ICMP_UNREACH:
case ICMP_SOURCEQUENCH:
case ICMP_REDIRECT:
case ICMP_TIMXCEED:
case ICMP_PARAMPROB:
/* Nodes are not supposed to respond to error messages, so
* we don't expect any replies. */
return false;
break;
case ICMP_ECHO:
/* For Echo request, we expect echo replies */
if(rcvd_icmp4->getType()!=ICMP_ECHOREPLY)
return false;
/* And we expect the ID and sequence number of the reply to
* match the ID and seq of the request. */
if(sent_icmp4->getIdentifier() != rcvd_icmp4->getIdentifier())
return false;
if(sent_icmp4->getSequence() != rcvd_icmp4->getSequence())
return false;
break;
case ICMP_ROUTERSOLICIT:
/* For ICMPv4 router solicitations, we expect router advertisements.
* We don't validate anything else because in IPv4 any advert that
* comes from the host we sent the solicitation to can be
* considered a response. */
if(rcvd_icmp4->getType()!=ICMP_ROUTERADVERT)
return false;
break;
case ICMP_ROUTERADVERT:
/* We don't expect responses to advertisements */
return false;
break;
case ICMP_TSTAMP:
/* For Timestampt requests, we expect timestamp replies */
if(rcvd_icmp4->getType()!=ICMP_TSTAMPREPLY)
return false;
/* And we expect the ID and sequence number of the reply to
* match the ID and seq of the request. */
if(sent_icmp4->getIdentifier() != rcvd_icmp4->getIdentifier())
return false;
if(sent_icmp4->getSequence() != rcvd_icmp4->getSequence())
return false;
break;
case ICMP_TSTAMPREPLY:
/* We do not expect responses to timestamp replies */
return false;
break;
case ICMP_INFO:
/* For Information requests, we expect Information replies */
if(rcvd_icmp4->getType()!=ICMP_INFOREPLY)
return false;
/* And we expect the ID and sequence number of the reply to
* match the ID and seq of the request. */
if(sent_icmp4->getIdentifier() != rcvd_icmp4->getIdentifier())
return false;
if(sent_icmp4->getSequence() != rcvd_icmp4->getSequence())
return false;
break;
case ICMP_INFOREPLY:
/* We do not expect responses to Information replies */
return false;
break;
case ICMP_MASK:
/* For Netmask requests, we expect Netmask replies */
if(rcvd_icmp4->getType()!=ICMP_MASKREPLY)
return false;
/* And we expect the ID and sequence number of the reply to
* match the ID and seq of the request. */
if(sent_icmp4->getIdentifier() != rcvd_icmp4->getIdentifier())
return false;
if(sent_icmp4->getSequence() != rcvd_icmp4->getSequence())
return false;
break;
case ICMP_MASKREPLY:
/* We do not expect responses to netmask replies */
return false;
break;
case ICMP_TRACEROUTE:
/* We don't expect replies to a traceroute message as it is
* sent as a response to an IP datagram that contains the
* IP traceroute option. Also, note that this function does
* not take this into account when processing IPv4 datagrams
* so if we receive an ICMP_TRACEROUTE we'll not be able
* to match it with the original IP datagram. */
return false;
break;
case ICMP_DOMAINNAME:
/* For Domain Name requests, we expect Domain Name replies */
if(rcvd_icmp4->getType()!=ICMP_DOMAINNAMEREPLY)
return false;
/* And we expect the ID and sequence number of the reply to
* match the ID and seq of the request. */
if(sent_icmp4->getIdentifier() != rcvd_icmp4->getIdentifier())
return false;
if(sent_icmp4->getSequence() != rcvd_icmp4->getSequence())
return false;
break;
case ICMP_DOMAINNAMEREPLY:
/* We do not expect replies to DN replies */
return false;
break;
case ICMP_SECURITYFAILURES:
/* Nodes are not expected to send replies to this message, as it
* is an ICMP error. */
return false;
break;
}
}else{
return false; // Should never happen
}
}
}else if(sent_layer4->protocol_id()==HEADER_TYPE_TCP || sent_layer4->protocol_id()==HEADER_TYPE_UDP){
if(PKTPARSERDEBUG)printf("%s(): Sent packet has a transport layer header.\n", __func__);
/* Both are TCP or both UDP */
if(sent_layer4->protocol_id()==rcvd_layer4->protocol_id()){
if(PKTPARSERDEBUG)printf("%s(): Received packet has a transport layer header too.\n", __func__);
/* Probe source port must equal response target port */
if( ((TransportLayerElement *)sent_layer4)->getSourcePort() != ((TransportLayerElement *)rcvd_layer4)->getDestinationPort() )
return false;
/* Probe target port must equal response source port */
if( ((TransportLayerElement *)rcvd_layer4)->getSourcePort() != ((TransportLayerElement *)sent_layer4)->getDestinationPort() )
return false;
/* If we sent TCP or UDP and got ICMP in response, we need to find a copy of our packet in the
* ICMP payload, providing it is an ICMP error message. */
}else if(rcvd_layer4->protocol_id()==HEADER_TYPE_ICMPv6 || rcvd_layer4->protocol_id()==HEADER_TYPE_ICMPv4){
if(PKTPARSERDEBUG)printf("%s(): Received packet does not have transport layer header but an ICMP header.\n", __func__);
/* We only expect ICMP error messages */
if( !(((ICMPHeader *)rcvd_layer4)->isError()) )
return false;
/* Let's validate the original header */
NetworkLayerElement *iperror=(NetworkLayerElement *)rcvd_layer4->getNextElement();
/* ICMP error message must contain the original datagram */
if(iperror==NULL)
return false;
/* The first header must be IP */
if(iperror->protocol_id()!=HEADER_TYPE_IPv6 && iperror->protocol_id()!=HEADER_TYPE_IPv4)
return false;
/* The IP version must match the probe's */
if(iperror->protocol_id()!=sent_ip->protocol_id())
return false;
/* Source and destination addresses must match the probe's (NATs are
* supposed to rewrite them too, so this should be OK) */
if( memcmp(iperror->getSourceAddress(), sent_ip->getSourceAddress(), iperror->getAddressLength())!=0 )
return false;
if( memcmp(iperror->getDestinationAddress(), sent_ip->getDestinationAddress(), iperror->getAddressLength())!=0 )
return false;
/* So far we've verified that the ICMP error contains an IP datagram that matches
* what we sent. Now, let's find the upper layer protocol (skip extension
* headers and the like until we find some transport protocol). */
TransportLayerElement *layer4error=(TransportLayerElement *)iperror->getNextElement();
while(layer4error!=NULL){
if(layer4error->protocol_id()==HEADER_TYPE_UDP || layer4error->protocol_id()==HEADER_TYPE_TCP ){
break;
}else{
layer4error=(TransportLayerElement *)layer4error->getNextElement();
}
}
if(layer4error==NULL)
return false;
/* Now make sure we see the same port numbers */
if( layer4error->getSourcePort() != ((TransportLayerElement *)sent_layer4)->getSourcePort() )
return false;
if( layer4error->getDestinationPort() != ((TransportLayerElement *)sent_layer4)->getDestinationPort() )
return false;
} else {
return false;
}
}else{
/* We sent a layer 4 other than ICMP, ICMPv6, TCP, or UDP. We return false
* as we cannot match responses for protocols we don't understand */
return false;
}
/* If we get there it means the packet passed all the tests. Return true
* to indicate that the packet is a response to this FPProbe. */
if(PKTPARSERDEBUG)printf("%s(): The received packet was successfully matched with the sent packet.\n", __func__);
return true;
}
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