FileAnalysis: optimize get_file_handle event queueing.

When a file handle is needed and the last event in the queue is also
a get_file_handle event with the same arguments, instead of queueing
a new event, just remember to cache/re-use the resulting handle from
the previous event.  This depends on get_file_handle handlers not
changing global state that is also used to derive the file handle
string.

scripts/base/protocols/ftp/file-analysis.bro

@@ -18,9 +18,6 @@ export {
 
 		local info: FTP::Info = ftp_data_expected[c$id$resp_h, c$id$resp_p];
 
-		local rval = fmt("%s %s %s", ANALYZER_FTP_DATA, c$start_time,
-		                 id_string(c$id));
-
 		if ( info$passive )
 			# FTP client initiates data channel.
 			if ( is_orig )
@@ -28,12 +25,14 @@ export {
 				return "";
 			else
 				# Do care about FTP server data.
-				return rval;
+				return cat(ANALYZER_FTP_DATA, " ", c$start_time, " ",
+				           id_string(c$id));
 		else
 			# FTP server initiates dta channel.
 			if ( is_orig )
 				# Do care about FTP server data.
-				return rval;
+				return cat(ANALYZER_FTP_DATA, " ", c$start_time, " ",
+				           id_string(c$id));
 			else
 				# Don't care about FTP client data.
 				return "";

scripts/base/protocols/http/file-analysis.bro

@@ -18,11 +18,11 @@ export {
 		if ( ! c?$http ) return "";
 
 		if ( c$http$range_request )
-			return fmt("%s %s %s %s", ANALYZER_HTTP, is_orig, c$id$orig_h,
-			           build_url(c$http));
+			return cat(ANALYZER_HTTP, " ", is_orig, " ", c$id$orig_h,
+			           " ", build_url(c$http));
 
-		return fmt("%s %s %s %s %s", ANALYZER_HTTP, c$start_time, is_orig,
-		           c$http$trans_depth, id_string(c$id));
+		return cat(ANALYZER_HTTP, " ", c$start_time, " ", is_orig,
+		           " ", c$http$trans_depth, " ", id_string(c$id));
 		}
 }
 

scripts/base/protocols/irc/file-analysis.bro

@@ -15,7 +15,7 @@ export {
 	function get_file_handle(c: connection, is_orig: bool): string
 		{
 		if ( is_orig ) return "";
-		return fmt("%s %s %s", ANALYZER_IRC_DATA, c$start_time,
+		return cat(ANALYZER_IRC_DATA, " ", c$start_time, " ",
 		           id_string(c$id));
 		}
 }

scripts/base/protocols/smtp/file-analysis.bro

@@ -17,8 +17,8 @@ export {
 		{
 		if ( ! c?$smtp ) return "";
 
-		return fmt("%s %s %s %s", ANALYZER_SMTP, c$start_time,
-		           c$smtp$trans_depth, c$smtp_state$mime_level);
+		return cat(ANALYZER_SMTP, " ", c$start_time, " ",
+		           c$smtp$trans_depth, " ", c$smtp_state$mime_level);
 		}
 }
 

src/Event.h

@@ -118,6 +118,9 @@ public:
 
 	void Describe(ODesc* d) const;
 
+	EventHandlerPtr Tail() { return tail ? tail->handler : EventHandlerPtr(); }
+	val_list* TailArgs() { return tail ? tail->args : 0; }
+
 protected:
 	void QueueEvent(Event* event);
 

src/event.bif

@@ -6986,7 +6986,8 @@ event bro_script_loaded%(path: string, level: count%);
 ## belongs.  All incoming data to the framework is buffered, and depends
 ## on a handler for this event to return a string value that uniquely
 ## identifies a file.  Among all handlers of this event, exactly one must
-## call :bro:see:`return_file_handle`.
+## call :bro:see:`return_file_handle`.  Handlers of this event must not
+## change any global state.
 ##
 ## tag: The analyzer which is carrying the file data.
 ##

src/file_analysis/Info.cc

@@ -185,6 +185,13 @@ double Info::GetTimeoutInterval() const
 	return LookupFieldDefaultInterval(timeout_interval_idx);
 	}
 
+string Info::GetSource() const
+	{
+	Val* v = val->Lookup(source_idx);
+	if ( ! v ) return "";
+	return v->AsStringVal()->CheckString();
+	}
+
 RecordVal* Info::GetResults(RecordVal* args) const
 	{
 	TableVal* actions_table = val->Lookup(actions_idx)->AsTableVal();
@@ -243,18 +250,6 @@ bool Info::BufferBOF(const u_char* data, uint64 len)
 
 	uint64 desired_size = LookupFieldDefaultCount(bof_buffer_size_idx);
 
-	/* Leaving out this optimization (I think) for now to keep things simpler.
-	// If first chunk satisfies desired size, do everything now without copying.
-	if ( bof_buffer.chunks.empty() && len >= desired_size )
-		{
-		bof_buffer.full = bof_buffer.replayed = true;
-		val->Assign(bof_buffer_idx, new StringVal(new BroString(data, len, 0)));
-		file_mgr->EvaluatePolicy(TRIGGER_BOF_BUFFER, this);
-		// TODO: libmagic stuff
-		return false;
-		}
-	*/
-
 	bof_buffer.chunks.push_back(new BroString(data, len, 0));
 	bof_buffer.size += len;
 

src/file_analysis/Info.h

@@ -32,6 +32,11 @@ public:
 	 */
 	double GetTimeoutInterval() const;
 
+	/**
+	 * @return value of the "source" field from #val record.
+	 */
+	string GetSource() const;
+
 	/**
 	 * @return value of the "file_id" field from #val record.
 	 */

src/file_analysis/Manager.cc

@@ -34,11 +34,17 @@ void Manager::ReceiveHandle(const string& handle)
 	if ( pending.empty() )
 		reporter->InternalError("File analysis underflow");
 
-	PendingFile* pf = pending.front();
-	if ( ! handle.empty() )
-		pf->Finish(handle);
-	delete pf;
-	pending.pop();
+	int use_count = cache.front();
+	cache.pop();
+
+	for ( int i = 0; i < use_count; ++i )
+		{
+		PendingFile* pf = pending.front();
+		if ( ! handle.empty() )
+			pf->Finish(handle);
+		delete pf;
+		pending.pop();
+		}
 	}
 
 void Manager::EventDrainDone()
@@ -330,11 +336,50 @@ bool Manager::IsDisabled(AnalyzerTag::Tag tag)
 	return rval;
 	}
 
+static bool CheckArgEquality(AnalyzerTag::Tag tag, Connection* conn,
+                             bool is_orig, val_list* other_args)
+	{
+	if ( ! other_args ) return false;
+	if ( (*other_args)[0]->AsCount() != (bro_uint_t) tag ) return false;
+	if ( (*other_args)[2]->AsBool() != is_orig ) return false;
+
+	RecordVal* id = (*other_args)[1]->AsRecordVal()->Lookup(
+	        connection_type->FieldOffset("id"))->AsRecordVal();
+
+	PortVal* orig_p = id->Lookup(
+	        conn_id->FieldOffset("orig_p"))->AsPortVal();
+
+	if ( orig_p->Port() != ntohs(conn->OrigPort()) ) return false;
+	if ( orig_p->PortType() != conn->ConnTransport() ) return false;
+
+	PortVal* resp_p = id->Lookup(
+	        conn_id->FieldOffset("resp_p"))->AsPortVal();
+
+	if ( resp_p->Port() != ntohs(conn->RespPort()) ) return false;
+
+	if ( id->Lookup(conn_id->FieldOffset("orig_h"))->AsAddr() !=
+	     conn->OrigAddr() ) return false;
+
+	if ( id->Lookup(conn_id->FieldOffset("resp_h"))->AsAddr() !=
+	     conn->RespAddr() ) return false;
+
+	return true;
+	}
+
 bool Manager::QueueHandleEvent(AnalyzerTag::Tag tag, Connection* conn,
                                bool is_orig)
 	{
 	if ( ! get_file_handle ) return false;
 
+	if ( mgr.Tail() == get_file_handle &&
+	     CheckArgEquality(tag, conn, is_orig, mgr.TailArgs()) )
+		{
+		cache.front()++;
+		return true;
+		}
+
+	cache.push(1);
+
 	val_list* vl = new val_list();
 	vl->append(new Val(tag, TYPE_COUNT));
 	vl->append(conn->BuildConnVal());

src/file_analysis/Manager.h

@@ -130,6 +130,7 @@ protected:
 	typedef set<string> StrSet;
 	typedef map<FileID, Info*> IDMap;
 	typedef queue<PendingFile*> PendingQueue;
+	typedef queue<int> HandleCache;
 
 	/**
 	 * @return the Info object mapped to \a unique or a null pointer if analysis
@@ -164,22 +165,24 @@ protected:
 	 */
 	bool IsIgnored(const string& unique);
 
-	/**
-	 * @return whether file analysis is disabled for the given analyzer.
-	 */
-	static bool IsDisabled(AnalyzerTag::Tag tag);
-
 	/**
 	 * Queues \c get_file_handle event in order to retrieve unique file handle.
 	 * @return true if there is a handler for the event, else false.
 	 */
-	static bool QueueHandleEvent(AnalyzerTag::Tag tag, Connection* conn,
-	                             bool is_orig);
+	bool QueueHandleEvent(AnalyzerTag::Tag tag, Connection* conn,
+	                      bool is_orig);
+
+	/**
+	 * @return whether file analysis is disabled for the given analyzer.
+	 */
+	static bool IsDisabled(AnalyzerTag::Tag tag);
 
 	StrMap str_map; /**< Map unique strings to \c FileAnalysis::Info records. */
 	IDMap id_map;   /**< Map file IDs to \c FileAnalysis::Info records. */
 	StrSet ignored; /**< Ignored files.  Will be finally removed on EOF. */
 	PendingQueue pending; /**< Files awaiting a unique handle. */
+	HandleCache cache; /**< The number of times a received file handle can be
+	                        used to pop the #pending queue. */
 
 	static TableVal* disabled; /**< Table of disabled analyzers. */
 };