zeek/src/packet_analysis/Analyzer.cc
2020-09-23 11:13:29 -07:00

135 lines
3.2 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#include "Analyzer.h"
#include "Dict.h"
#include "DebugLogger.h"
namespace zeek::packet_analysis {
Analyzer::Analyzer(std::string name)
{
Tag t = packet_mgr->GetComponentTag(name);
if ( ! t )
reporter->InternalError("unknown packet_analysis name %s", name.c_str());
Init(t);
}
Analyzer::Analyzer(const Tag& tag)
{
Init(tag);
}
void Analyzer::Init(const Tag& _tag)
{
tag = _tag;
}
void Analyzer::Initialize()
{
default_analyzer = LoadAnalyzer("default_analyzer");
// Create dispatcher based on configuration
auto& mapping_id = zeek::id::find(GetModuleName() + "dispatch_map");
if ( ! mapping_id )
return;
auto mapping_val = mapping_id->GetVal()->AsTableVal();
auto mapping_tbl = mapping_val->AsTable();
auto c = mapping_tbl->InitForIteration();
zeek::detail::HashKey* k = nullptr;
TableEntryVal* v;
while ( (v = mapping_tbl->NextEntry(k, c)) )
{
auto key = mapping_val->RecreateIndex(*k);
delete k;
auto identifier = key->Idx(0)->AsCount();
auto config_entry_val = v->GetVal()->AsRecordVal();
auto mapped_tag = config_entry_val->GetField("analyzer")->AsEnumVal();
auto mapped_analyzer = packet_mgr->GetAnalyzer(mapped_tag);
dispatcher.Register(identifier, std::move(mapped_analyzer));
}
}
zeek::packet_analysis::AnalyzerPtr Analyzer::LoadAnalyzer(const std::string &name)
{
auto& analyzer = zeek::id::find(GetModuleName() + name);
if ( ! analyzer )
return nullptr;
auto& analyzer_val = analyzer->GetVal();
if ( ! analyzer_val )
return nullptr;
return packet_mgr->GetAnalyzer(analyzer_val->AsEnumVal());
}
const Tag Analyzer::GetAnalyzerTag() const
{
assert(tag);
return tag;
}
const char* Analyzer::GetAnalyzerName() const
{
assert(tag);
return packet_mgr->GetComponentName(tag).c_str();
}
bool Analyzer::IsAnalyzer(const char* name)
{
assert(tag);
return packet_mgr->GetComponentName(tag) == name;
}
AnalyzerPtr Analyzer::Lookup(uint32_t identifier) const
{
return dispatcher.Lookup(identifier);
}
bool Analyzer::ForwardPacket(size_t len, const uint8_t* data, Packet* packet,
uint32_t identifier) const
{
auto inner_analyzer = Lookup(identifier);
if ( ! inner_analyzer )
inner_analyzer = default_analyzer;
if ( inner_analyzer == nullptr )
{
DBG_LOG(DBG_PACKET_ANALYSIS, "Analysis in %s failed, could not find analyzer for identifier %#x.",
GetAnalyzerName(), identifier);
packet->Weird("no_suitable_analyzer_found");
return false;
}
DBG_LOG(DBG_PACKET_ANALYSIS, "Analysis in %s succeeded, next layer identifier is %#x.",
GetAnalyzerName(), identifier);
return inner_analyzer->AnalyzePacket(len, data, packet);
}
bool Analyzer::ForwardPacket(size_t len, const uint8_t* data, Packet* packet) const
{
if ( default_analyzer )
return default_analyzer->AnalyzePacket(len, data, packet);
DBG_LOG(DBG_PACKET_ANALYSIS, "Analysis in %s stopped, no default analyzer available.",
GetAnalyzerName());
packet->Weird("no_suitable_analyzer_found");
return true;
}
void Analyzer::DumpDebug() const
{
#ifdef DEBUG
DBG_LOG(DBG_PACKET_ANALYSIS, "Dispatcher for %s", this->GetAnalyzerName());
dispatcher.DumpDebug();
#endif
}
}