mirror of
https://github.com/zeek/zeek.git
synced 2025-10-15 13:08:20 +00:00
modify DNP3.cc and DNP3.h to add DNP3_UDP_Analyzer; binpac unchanged
This commit is contained in:
Hui Lin
parent
f8bb17bcb8
commit
cd81eaedca
2 changed files with 317 additions and 0 deletions
|
|
@ -112,6 +112,10 @@ const unsigned int PSEUDO_LINK_LAYER_LEN = 8; // length of DNP3 Pseudo Link Lay
|
|||
bool DNP3_Analyzer::crc_table_initialized = false;
|
||||
unsigned int DNP3_Analyzer::crc_table[256];
|
||||
|
||||
bool DNP3_UDP_Analyzer::crc_table_initialized = false;
|
||||
unsigned int DNP3_UDP_Analyzer::crc_table[256];
|
||||
|
||||
|
||||
DNP3_Analyzer::DNP3_Analyzer(Connection* c) : TCP_ApplicationAnalyzer("DNP3", c)
|
||||
{
|
||||
interp = new binpac::DNP3::DNP3_Conn(this);
|
||||
|
|
@ -374,3 +378,269 @@ unsigned int DNP3_Analyzer::CalcCRC(int len, const u_char* data)
|
|||
|
||||
return ~crc & 0xFFFF;
|
||||
}
|
||||
|
||||
// ?? For DNP3 over UDP analyzer. most of the codes are copied and pasted. Better way to reuse the code?
|
||||
|
||||
DNP3_UDP_Analyzer::DNP3_UDP_Analyzer(Connection* c) : Analyzer("DHCP", c)
|
||||
{
|
||||
interp = new binpac::DNP3::DNP3_Conn(this);
|
||||
|
||||
ClearEndpointState(true);
|
||||
ClearEndpointState(false);
|
||||
|
||||
if ( ! crc_table_initialized )
|
||||
PrecomputeCRCTable();
|
||||
}
|
||||
|
||||
DNP3_UDP_Analyzer::~DNP3_UDP_Analyzer()
|
||||
{
|
||||
delete interp;
|
||||
}
|
||||
|
||||
void DNP3_UDP_Analyzer::Done()
|
||||
{
|
||||
Analyzer::Done();
|
||||
|
||||
interp->FlowEOF(true);
|
||||
interp->FlowEOF(false);
|
||||
}
|
||||
|
||||
void DNP3_UDP_Analyzer::DeliverStream(int len, const u_char* data, bool orig)
|
||||
{
|
||||
Analyzer::DeliverStream(len, data, orig);
|
||||
|
||||
try
|
||||
{
|
||||
if ( ! ProcessData(len, data, orig) )
|
||||
SetSkip(1);
|
||||
}
|
||||
|
||||
catch ( const binpac::Exception& e )
|
||||
{
|
||||
SetSkip(1);
|
||||
throw;
|
||||
}
|
||||
}
|
||||
/*
|
||||
void DNP3_UDP_Analyzer::Undelivered(uint64 seq, int len, bool orig)
|
||||
{
|
||||
Analyzer::Undelivered(seq, len, orig);
|
||||
interp->NewGap(orig, len);
|
||||
}
|
||||
|
||||
void DNP3_UDP_Analyzer::EndpointEOF(bool is_orig)
|
||||
{
|
||||
Analyzer::EndpointEOF(is_orig);
|
||||
interp->FlowEOF(is_orig);
|
||||
}
|
||||
*/
|
||||
|
||||
bool DNP3_UDP_Analyzer::ProcessData(int len, const u_char* data, bool orig)
|
||||
{
|
||||
Endpoint* endp = orig ? &orig_state : &resp_state;
|
||||
|
||||
while ( len )
|
||||
{
|
||||
if ( endp->in_hdr )
|
||||
{
|
||||
// We're parsing the DNP3 header and link layer, get that in full.
|
||||
if ( ! AddToBuffer(endp, PSEUDO_APP_LAYER_INDEX, &data, &len) )
|
||||
return true;
|
||||
|
||||
// The first two bytes must always be 0x0564.
|
||||
if( endp->buffer[0] != 0x05 || endp->buffer[1] != 0x64 )
|
||||
{
|
||||
Weird("dnp3_header_lacks_magic");
|
||||
return false;
|
||||
}
|
||||
|
||||
// Make sure header checksum is correct.
|
||||
if ( ! CheckCRC(PSEUDO_LINK_LAYER_LEN, endp->buffer, endp->buffer + PSEUDO_LINK_LAYER_LEN, "header") )
|
||||
{
|
||||
ProtocolViolation("broken_checksum");
|
||||
return false;
|
||||
}
|
||||
|
||||
// If the checksum works out, we're pretty certainly DNP3.
|
||||
ProtocolConfirmation();
|
||||
|
||||
// DNP3 packets without transport and application
|
||||
// layers can happen, we ignore them.
|
||||
if ( (endp->buffer[PSEUDO_LENGTH_INDEX] + 3) == (char)PSEUDO_LINK_LAYER_LEN )
|
||||
{
|
||||
ClearEndpointState(orig);
|
||||
return true;
|
||||
}
|
||||
|
||||
// Double check the direction in case the first
|
||||
// received packet is a response.
|
||||
u_char ctrl = endp->buffer[PSEUDO_CONTROL_FIELD_INDEX];
|
||||
|
||||
if ( orig != (bool)(ctrl & 0x80) )
|
||||
Weird("dnp3_unexpected_flow_direction");
|
||||
|
||||
// Update state.
|
||||
endp->pkt_length = endp->buffer[PSEUDO_LENGTH_INDEX];
|
||||
endp->tpflags = endp->buffer[PSEUDO_TRANSPORT_INDEX];
|
||||
endp->in_hdr = false; // Now parsing application layer.
|
||||
|
||||
// For the first packet, we submit the header to
|
||||
// BinPAC.
|
||||
if ( ++endp->pkt_cnt == 1 )
|
||||
interp->NewData(orig, endp->buffer, endp->buffer + PSEUDO_LINK_LAYER_LEN);
|
||||
}
|
||||
|
||||
if ( ! endp->in_hdr )
|
||||
{
|
||||
assert(endp->pkt_length);
|
||||
|
||||
// We're parsing the DNP3 application layer, get that
|
||||
// in full now as well. We calculate the number of
|
||||
// raw bytes the application layer consists of from
|
||||
// the packet length by determining how much 16-byte
|
||||
// chunks fit in there, and then add 2 bytes CRC for
|
||||
// each.
|
||||
int n = PSEUDO_APP_LAYER_INDEX + (endp->pkt_length - 5) + ((endp->pkt_length - 5) / 16) * 2 + 2 - 1;
|
||||
|
||||
if ( ! AddToBuffer(endp, n, &data, &len) )
|
||||
return true;
|
||||
|
||||
// Parse the the application layer data.
|
||||
if ( ! ParseAppLayer(endp) )
|
||||
return false;
|
||||
|
||||
// Done with this packet, prepare for next.
|
||||
endp->buffer_len = 0;
|
||||
endp->in_hdr = true;
|
||||
}
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
bool DNP3_UDP_Analyzer::AddToBuffer(Endpoint* endp, int target_len, const u_char** data, int* len)
|
||||
{
|
||||
if ( ! target_len )
|
||||
return true;
|
||||
|
||||
int to_copy = min(*len, target_len - endp->buffer_len);
|
||||
|
||||
memcpy(endp->buffer + endp->buffer_len, *data, to_copy);
|
||||
*data += to_copy;
|
||||
*len -= to_copy;
|
||||
endp->buffer_len += to_copy;
|
||||
|
||||
return endp->buffer_len == target_len;
|
||||
}
|
||||
|
||||
bool DNP3_UDP_Analyzer::ParseAppLayer(Endpoint* endp)
|
||||
{
|
||||
bool orig = (endp == &orig_state);
|
||||
binpac::DNP3::DNP3_Flow* flow = orig ? interp->upflow() : interp->downflow();
|
||||
|
||||
u_char* data = endp->buffer + PSEUDO_TRANSPORT_INDEX; // The transport layer byte counts as app-layer it seems.
|
||||
int len = endp->pkt_length - 5;
|
||||
|
||||
// DNP3 Packet : DNP3 Pseudo Link Layer | DNP3 Pseudo Transport Layer | DNP3 Pseudo Application Layer
|
||||
// DNP3 Serial Transport Layer data is always 1 byte.
|
||||
// Get FIN FIR seq field in transport header.
|
||||
// FIR indicate whether the following DNP3 Serial Application Layer is first chunk of bytes or not.
|
||||
// FIN indicate whether the following DNP3 Serial Application Layer is last chunk of bytes or not.
|
||||
|
||||
int is_first = (endp->tpflags & 0x40) >> 6; // Initial chunk of data in this packet.
|
||||
int is_last = (endp->tpflags & 0x80) >> 7; // Last chunk of data in this packet.
|
||||
|
||||
int transport = PSEUDO_TRANSPORT_LEN;
|
||||
|
||||
int i = 0;
|
||||
while ( len > 0 )
|
||||
{
|
||||
int n = min(len, 16);
|
||||
|
||||
// Make sure chunk has a correct checksum.
|
||||
if ( ! CheckCRC(n, data, data + n, "app_chunk") )
|
||||
return false;
|
||||
|
||||
// Pass on to BinPAC.
|
||||
assert(data + n < endp->buffer + endp->buffer_len);
|
||||
flow->flow_buffer()->BufferData(data + transport, data + n);
|
||||
transport = 0;
|
||||
|
||||
data += n + 2;
|
||||
len -= n;
|
||||
}
|
||||
|
||||
if ( is_first )
|
||||
endp->encountered_first_chunk = true;
|
||||
|
||||
if ( ! is_first && ! endp->encountered_first_chunk )
|
||||
{
|
||||
// We lost the first chunk.
|
||||
Weird("dnp3_first_application_layer_chunk_missing");
|
||||
return false;
|
||||
}
|
||||
|
||||
if ( is_last )
|
||||
{
|
||||
flow->flow_buffer()->FinishBuffer();
|
||||
flow->FlowEOF();
|
||||
ClearEndpointState(orig);
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
void DNP3_UDP_Analyzer::ClearEndpointState(bool orig)
|
||||
{
|
||||
Endpoint* endp = orig ? &orig_state : &resp_state;
|
||||
binpac::DNP3::DNP3_Flow* flow = orig ? interp->upflow() : interp->downflow();
|
||||
|
||||
endp->in_hdr = true;
|
||||
endp->encountered_first_chunk = false;
|
||||
endp->buffer_len = 0;
|
||||
endp->pkt_length = 0;
|
||||
endp->tpflags = 0;
|
||||
endp->pkt_cnt = 0;
|
||||
}
|
||||
|
||||
bool DNP3_UDP_Analyzer::CheckCRC(int len, const u_char* data, const u_char* crc16, const char* where)
|
||||
{
|
||||
unsigned int crc = CalcCRC(len, data);
|
||||
|
||||
if ( crc16[0] == (crc & 0xff) && crc16[1] == (crc & 0xff00) >> 8 )
|
||||
return true;
|
||||
|
||||
Weird(fmt("dnp3_corrupt_%s_checksum", where));
|
||||
return false;
|
||||
}
|
||||
|
||||
void DNP3_UDP_Analyzer::PrecomputeCRCTable()
|
||||
{
|
||||
for( unsigned int i = 0; i < 256; i++)
|
||||
{
|
||||
unsigned int crc = i;
|
||||
|
||||
for ( unsigned int j = 0; j < 8; ++j )
|
||||
{
|
||||
if ( crc & 0x0001 )
|
||||
crc = (crc >> 1) ^ 0xA6BC; // Generating polynomial.
|
||||
else
|
||||
crc >>= 1;
|
||||
}
|
||||
|
||||
crc_table[i] = crc;
|
||||
}
|
||||
}
|
||||
|
||||
unsigned int DNP3_UDP_Analyzer::CalcCRC(int len, const u_char* data)
|
||||
{
|
||||
unsigned int crc = 0x0000;
|
||||
|
||||
for ( int i = 0; i < len; i++ )
|
||||
{
|
||||
unsigned int index = (crc ^ data[i]) & 0xFF;
|
||||
crc = crc_table[index] ^ (crc >> 8);
|
||||
}
|
||||
|
||||
return ~crc & 0xFFFF;
|
||||
}
|
||||
|
|
|
|||
|
|
@ -3,6 +3,8 @@
|
|||
#define ANALYZER_PROTOCOL_DNP3_DNP3_H
|
||||
|
||||
#include "analyzer/protocol/tcp/TCP.h"
|
||||
#include "analyzer/protocol/udp/UDP.h"
|
||||
|
||||
#include "dnp3_pac.h"
|
||||
|
||||
namespace analyzer { namespace dnp3 {
|
||||
|
|
@ -51,6 +53,51 @@ private:
|
|||
static unsigned int crc_table[256];
|
||||
};
|
||||
|
||||
class DNP3_UDP_Analyzer : public analyzer::Analyzer {
|
||||
public:
|
||||
DNP3_UDP_Analyzer(Connection* conn);
|
||||
virtual ~DNP3_UDP_Analyzer();
|
||||
|
||||
virtual void Done();
|
||||
virtual void DeliverStream(int len, const u_char* data, bool orig);
|
||||
//virtual void Undelivered(uint64 seq, int len, bool orig);
|
||||
//virtual void EndpointEOF(bool is_orig);
|
||||
|
||||
static Analyzer* Instantiate(Connection* conn)
|
||||
{ return new DNP3_UDP_Analyzer(conn); }
|
||||
|
||||
private:
|
||||
static const int MAX_BUFFER_SIZE = 300;
|
||||
|
||||
struct Endpoint {
|
||||
u_char buffer[MAX_BUFFER_SIZE];
|
||||
int buffer_len;
|
||||
bool in_hdr;
|
||||
int tpflags;
|
||||
int pkt_length;
|
||||
int pkt_cnt;
|
||||
bool encountered_first_chunk;
|
||||
};
|
||||
|
||||
bool ProcessData(int len, const u_char* data, bool orig);
|
||||
void ClearEndpointState(bool orig);
|
||||
bool AddToBuffer(Endpoint* endp, int target_len, const u_char** data, int* len);
|
||||
bool ParseAppLayer(Endpoint* endp);
|
||||
bool CheckCRC(int len, const u_char* data, const u_char* crc16, const char* where);
|
||||
unsigned int CalcCRC(int len, const u_char* data);
|
||||
|
||||
binpac::DNP3::DNP3_Conn* interp;
|
||||
|
||||
Endpoint orig_state;
|
||||
Endpoint resp_state;
|
||||
|
||||
static void PrecomputeCRCTable();
|
||||
|
||||
static bool crc_table_initialized;
|
||||
static unsigned int crc_table[256];
|
||||
};
|
||||
|
||||
|
||||
} } // namespace analyzer::*
|
||||
|
||||
#endif
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue