zeek/src/BitTorrent.cc
2011-08-04 15:21:18 -05:00

122 lines
3 KiB
C++

// This code contributed by Nadi Sarrar.
#include "BitTorrent.h"
#include "TCP_Reassembler.h"
BitTorrent_Analyzer::BitTorrent_Analyzer(Connection* c)
: TCP_ApplicationAnalyzer(AnalyzerTag::BitTorrent, c)
{
interp = new binpac::BitTorrent::BitTorrent_Conn(this);
stop_orig = stop_resp = false;
stream_len_orig = stream_len_resp = 0;
}
BitTorrent_Analyzer::~BitTorrent_Analyzer()
{
delete interp;
}
void BitTorrent_Analyzer::Done()
{
TCP_ApplicationAnalyzer::Done();
interp->FlowEOF(true);
interp->FlowEOF(false);
}
void BitTorrent_Analyzer::DeliverStream(int len, const u_char* data, bool orig)
{
uint64& this_stream_len = orig ? stream_len_orig : stream_len_resp;
bool& this_stop = orig ? stop_orig : stop_resp;
TCP_ApplicationAnalyzer::DeliverStream(len, data, orig);
assert(TCP());
if ( TCP()->IsPartial() )
// punt on partial.
return;
if ( this_stop )
return;
this_stream_len += len;
try
{
interp->NewData(orig, data, data + len);
}
catch ( binpac::Exception const &e )
{
const char except[] = "binpac exception: invalid handshake";
if ( ! strncmp(e.c_msg(), except, strlen(except)) )
// Does not look like bittorrent - silently
// drop the connection.
Parent()->RemoveChildAnalyzer(this);
else
{
DeliverWeird(fmt("Stopping BitTorrent analysis: protocol violation (%s)",
e.c_msg()), orig);
this_stop = true;
if ( stop_orig && stop_resp )
ProtocolViolation("BitTorrent: content gap and/or protocol violation");
}
}
}
void BitTorrent_Analyzer::Undelivered(int seq, int len, bool orig)
{
uint64 entry_offset = orig ?
*interp->upflow()->next_message_offset() :
*interp->downflow()->next_message_offset();
uint64& this_stream_len = orig ? stream_len_orig : stream_len_resp;
bool& this_stop = orig ? stop_orig : stop_resp;
TCP_ApplicationAnalyzer::Undelivered(seq, len, orig);
this_stream_len += len;
if ( entry_offset < this_stream_len )
{ // entry point is somewhere in the gap
DeliverWeird("Stopping BitTorrent analysis: cannot recover from content gap", orig);
this_stop = true;
if ( stop_orig && stop_resp )
ProtocolViolation("BitTorrent: content gap and/or protocol violation");
}
else
{ // fill the gap
try
{
u_char gap[len];
memset(gap, 0, len);
interp->NewData(orig, gap, gap + len);
}
catch ( binpac::Exception const &e )
{
DeliverWeird("Stopping BitTorrent analysis: filling content gap failed", orig);
this_stop = true;
if ( stop_orig && stop_resp )
ProtocolViolation("BitTorrent: content gap and/or protocol violation");
}
}
}
void BitTorrent_Analyzer::EndpointEOF(TCP_Reassembler* endp)
{
TCP_ApplicationAnalyzer::EndpointEOF(endp);
interp->FlowEOF(endp->IsOrig());
}
void BitTorrent_Analyzer::DeliverWeird(const char* msg, bool orig)
{
if ( bittorrent_peer_weird )
{
val_list* vl = new val_list;
vl->append(BuildConnVal());
vl->append(new Val(orig, TYPE_BOOL));
vl->append(new StringVal(msg));
ConnectionEvent(bittorrent_peer_weird, vl);
}
else
Weird(msg);
}