Teach async DNS lookup builtin-functions about BRO_DNS_FAKE.

And enable fake DNS mode for test suites.

Addresses BIT-1134.

src/DNS_Mgr.cc

@@ -443,6 +443,20 @@ bool DNS_Mgr::Init()
 	return true;
 	}
 
+TableVal* DNS_Mgr::BuildFakeAddrResult()
+	{
+	ListVal* hv = new ListVal(TYPE_ADDR);
+	hv->Append(new AddrVal(++dns_fake_count));
+	return hv->ConvertToSet();
+	}
+
+const char* DNS_Mgr::BuildFakeNameResult()
+	{
+	static char tmp[32];
+	snprintf(tmp, sizeof(tmp), "fake_result_%"PRIu32, ++dns_fake_count);
+	return tmp;
+	}
+
 TableVal* DNS_Mgr::LookupHost(const char* name)
 	{
 	if ( ! nb_dns )
@@ -452,11 +466,7 @@ TableVal* DNS_Mgr::LookupHost(const char* name)
 		Init();
 
 	if ( mode == DNS_FAKE )
-		{
+		return BuildFakeAddrResult();
-		ListVal* hv = new ListVal(TYPE_ADDR);
-		hv->Append(new AddrVal(uint32(++dns_fake_count)));
-		return hv->ConvertToSet();
-		}
 
 	if ( mode != DNS_PRIME )
 		{
@@ -960,7 +970,7 @@ const char* DNS_Mgr::LookupAddrInCache(const IPAddr& addr)
 	return d->names ? d->names[0] : "<\?\?\?>";
 	}
 
-TableVal* DNS_Mgr::LookupNameInCache(string name)
+TableVal* DNS_Mgr::LookupNameInCache(const string& name)
 	{
 	HostMap::iterator it = host_mappings.find(name);
 	if ( it == host_mappings.end() )
@@ -990,7 +1000,7 @@ TableVal* DNS_Mgr::LookupNameInCache(string name)
 	return tv6;
 	}
 
-const char* DNS_Mgr::LookupTextInCache(string name)
+const char* DNS_Mgr::LookupTextInCache(const string& name)
 	{
 	TextMap::iterator it = text_mappings.find(name);
 	if ( it == text_mappings.end() )
@@ -1010,17 +1020,37 @@ const char* DNS_Mgr::LookupTextInCache(string name)
 	return d->names ? d->names[0] : "<\?\?\?>";
 	}
 
+static void resolve_lookup_cb(DNS_Mgr::LookupCallback* callback,
+                              TableVal* result)
+	{
+	callback->Resolved(result);
+	Unref(result);
+	delete callback;
+	}
+
+static void resolve_lookup_cb(DNS_Mgr::LookupCallback* callback,
+                              const char* result)
+	{
+	callback->Resolved(result);
+	delete callback;
+	}
+
 void DNS_Mgr::AsyncLookupAddr(const IPAddr& host, LookupCallback* callback)
 	{
 	if ( ! did_init )
 		Init();
 
+	if ( mode == DNS_FAKE )
+		{
+		resolve_lookup_cb(callback, BuildFakeNameResult());
+		return;
+		}
+
 	// Do we already know the answer?
 	const char* name = LookupAddrInCache(host);
 	if ( name )
 		{
-		callback->Resolved(name);
+		resolve_lookup_cb(callback, name);
-		delete callback;
 		return;
 		}
 
@@ -1044,18 +1074,22 @@ void DNS_Mgr::AsyncLookupAddr(const IPAddr& host, LookupCallback* callback)
 	IssueAsyncRequests();
 	}
 
-void DNS_Mgr::AsyncLookupName(string name, LookupCallback* callback)
+void DNS_Mgr::AsyncLookupName(const string& name, LookupCallback* callback)
 	{
 	if ( ! did_init )
 		Init();
 
+	if ( mode == DNS_FAKE )
+		{
+		resolve_lookup_cb(callback, BuildFakeAddrResult());
+		return;
+		}
+
 	// Do we already know the answer?
 	TableVal* addrs = LookupNameInCache(name);
 	if ( addrs )
 		{
-		callback->Resolved(addrs);
+		resolve_lookup_cb(callback, addrs);
-		Unref(addrs);
-		delete callback;
 		return;
 		}
 
@@ -1079,13 +1113,25 @@ void DNS_Mgr::AsyncLookupName(string name, LookupCallback* callback)
 	IssueAsyncRequests();
 	}
 
-void DNS_Mgr::AsyncLookupNameText(string name, LookupCallback* callback)
+void DNS_Mgr::AsyncLookupNameText(const string& name, LookupCallback* callback)
 	{
 	if ( ! did_init )
 		Init();
 
+	if ( mode == DNS_FAKE )
+		{
+		resolve_lookup_cb(callback, BuildFakeNameResult());
+		return;
+		}
+
 	// Do we already know the answer?
-	TableVal* addrs;
+	const char* txt = LookupTextInCache(name);
+
+	if ( txt )
+		{
+		resolve_lookup_cb(callback, txt);
+		return;
+		}
 
 	AsyncRequest* req = 0;
 

src/DNS_Mgr.h

@@ -62,8 +62,8 @@ public:
 	int Save();
 
 	const char* LookupAddrInCache(const IPAddr& addr);
-	TableVal* LookupNameInCache(string name);
+	TableVal* LookupNameInCache(const string& name);
-	const char* LookupTextInCache(string name);
+	const char* LookupTextInCache(const string& name);
 
 	// Support for async lookups.
 	class LookupCallback {
@@ -77,8 +77,8 @@ public:
 	};
 
 	void AsyncLookupAddr(const IPAddr& host, LookupCallback* callback);
-	void AsyncLookupName(string name, LookupCallback* callback);
+	void AsyncLookupName(const string& name, LookupCallback* callback);
-	void AsyncLookupNameText(string name, LookupCallback* callback);
+	void AsyncLookupNameText(const string& name, LookupCallback* callback);
 
 	struct Stats {
 		unsigned long requests;	// These count only async requests.
@@ -102,6 +102,9 @@ protected:
 
 	Val* BuildMappingVal(DNS_Mapping* dm);
 
+	TableVal* BuildFakeAddrResult();
+	const char* BuildFakeNameResult();
+
 	void AddResult(DNS_Mgr_Request* dr, struct nb_dns_result* r);
 	void CompareMappings(DNS_Mapping* prev_dm, DNS_Mapping* new_dm);
 	ListVal* AddrListDelta(ListVal* al1, ListVal* al2);
@@ -163,7 +166,7 @@ protected:
 
 	RecordType* dm_rec;
 
-	int dns_fake_count;	// used to generate unique fake replies
+	uint32 dns_fake_count;	// used to generate unique fake replies
 
 	typedef list<LookupCallback*> CallbackList;
 

testing/btest/Baseline/core.fake_dns/out

@@ -0,0 +1,10 @@
+{
+3.0.0.0,
+2.0.0.0,
+1.0.0.0
+}
+lookup_hostname_txt, fake_result_4
+lookup_hostname, {
+5.0.0.0
+}
+lookup_addr, fake_result_6

testing/btest/btest.cfg

@@ -24,3 +24,4 @@ TEST_DIFF_CANONIFIER=%(testbase)s/../scripts/diff-canonifier
 TMPDIR=%(testbase)s/.tmp
 BRO_PROFILER_FILE=%(testbase)s/.tmp/script-coverage.XXXXXX
 BTEST_RST_FILTER=$SCRIPTS/rst-filter
+BRO_DNS_FAKE=1

testing/btest/core/fake_dns.bro

@@ -0,0 +1,41 @@
+# @TEST-EXEC: BRO_DNS_FAKE=1 bro -b %INPUT >out
+# @TEST-EXEC: btest-diff out
+
+redef exit_only_after_terminate = T;
+
+global addrs: set[addr] = {
+	google.com,
+	bing.com,
+	yahoo.com
+};
+
+global c: count = 0;
+
+function check_terminate()
+	{
+	++c;
+
+	if ( c > 2 )
+		terminate();
+	}
+
+event bro_init()
+	{
+	print addrs;
+
+	when ( local result = lookup_hostname_txt("bro.wp.dg.cx") )
+		{
+		print "lookup_hostname_txt", result;
+		check_terminate();
+		}
+	when ( local result2 = lookup_hostname("example.com") )
+		{
+		print "lookup_hostname", result2;
+		check_terminate();
+		}
+	when ( local result3 = lookup_addr(1.2.3.4) )
+		{
+		print "lookup_addr", result3;
+		check_terminate();
+		}
+	}

testing/btest/language/timeout.bro

@@ -1,4 +1,4 @@
-# @TEST-EXEC: bro -b %INPUT >out
+# @TEST-EXEC: unset BRO_DNS_FAKE && bro -b %INPUT >out
 # @TEST-EXEC: btest-diff out
 
 

testing/external/subdir-btest.cfg

@@ -19,3 +19,4 @@ SCRIPTS=%(testbase)s/../scripts
 DIST=%(testbase)s/../../..
 BUILD=%(testbase)s/../../../build
 BRO_PROFILER_FILE=%(testbase)s/.tmp/script-coverage.XXXXXX
+BRO_DNS_FAKE=1