Add check_subnet bif that allows exact membership test for subnet tables.

This commit also fixes a few small bugs introduced in the last patricia
tree commit.

src/PrefixTable.cc

@@ -106,7 +106,7 @@ list<IPPrefix> PrefixTable::FindAll(const IPAddr& addr, int width) const
 
 list<IPPrefix> PrefixTable::FindAll(const SubNetVal* value) const
 	{
-	return FindAll(value->AsSubNet().Prefix(), value->AsSubNet().LengthIPv6());
+	return FindAll(value->AsSubNet().Prefix(), value->AsSubNet().Length());
 	}
 
 void* PrefixTable::Lookup(const IPAddr& addr, int width, bool exact) const
@@ -132,12 +132,12 @@ void* PrefixTable::Lookup(const Val* value, bool exact) const
 
 	switch ( value->Type()->Tag() ) {
 	case TYPE_ADDR:
-		return Lookup(value->AsAddr(), 128, exact);
+		return Lookup(value->AsAddr(), value->AsAddr().GetFamily() == IPv4 ? 32 : 128, exact);
 		break;
 
 	case TYPE_SUBNET:
 		return Lookup(value->AsSubNet().Prefix(),
-				value->AsSubNet().LengthIPv6(), exact);
+				value->AsSubNet().Length(), exact);
 		break;
 
 	default:
@@ -171,12 +171,12 @@ void* PrefixTable::Remove(const Val* value)
 
 	switch ( value->Type()->Tag() ) {
 	case TYPE_ADDR:
-		return Remove(value->AsAddr(), 128);
+		return Remove(value->AsAddr(), value->AsAddr().GetFamily() == IPv4 ? 32 : 128);
 		break;
 
 	case TYPE_SUBNET:
 		return Remove(value->AsSubNet().Prefix(),
-				value->AsSubNet().LengthIPv6());
+				value->AsSubNet().Length());
 		break;
 
 	default:

src/bro.bif

@@ -1065,6 +1065,36 @@ function matching_subnets%(search: subnet, t: any%): subnet_vec
 	return result_v;
 	%}
 
+## Checks if a specific subnet is a member of a set/table[subnet].
+## In difference to the in operator, this performs an exact match, not
+## a longest prefix match
+##
+## search: the subnet to search for.
+##
+## t: the set[subnet] or table[subnet].
+##
+##
+## Returns: True if the exact subnet is a member, false otherwise.
+function check_subnet%(search: subnet, t: any%): bool
+	%{
+	if ( t->Type()->Tag() != TYPE_TABLE || ! t->Type()->AsTableType()->IsSubNetIndex() )
+		{
+		reporter->Error("matching_subnets needs to be called on a set[subnet]/table[subnet].");
+		return nullptr;
+		}
+
+	const PrefixTable* pt = t->AsTableVal()->Subnets();
+	if ( !pt )
+		{
+		reporter->Error("matching_subnets encountered nonexisting prefix table.");
+		return nullptr;
+		}
+
+	void* res = pt->Lookup(search, true);
+
+	return new Val (res != nullptr, TYPE_BOOL);
+	%}
+
 ## Checks whether two objects reference the same internal object. This function
 ## uses equality comparison of C++ raw pointer values to determine if the two
 ## objects are the same.

testing/btest/Baseline/bifs.check_subnet/output

@@ -0,0 +1,8 @@
+in says: 10.2.0.2/32 is member
+check_subnet says: 10.2.0.2/32 is no member
+in says: 10.2.0.2/31 is member
+check_subnet says: 10.2.0.2/31 is member
+in says: 10.0.0.0/9 is member
+check_subnet says: 10.0.0.0/9 is no member
+in says: 10.0.0.0/8 is member
+check_subnet says: 10.0.0.0/8 is member

testing/btest/bifs/check_subnet.bro

@@ -0,0 +1,39 @@
+# @TEST-EXEC: bro -b %INPUT >output
+# @TEST-EXEC: btest-diff output
+
+global testt: set[subnet] = {
+	10.0.0.0/8,
+	10.2.0.0/16,
+	10.2.0.2/31,
+	10.1.0.0/16,
+	10.3.0.0/16,
+	5.0.0.0/8,
+	5.5.0.0/25,
+	5.2.0.0/32,
+	7.2.0.0/32,
+	[2607:f8b0:4008:807::200e]/64,
+	[2607:f8b0:4007:807::200e]/64,
+	[2607:f8b0:4007:807::200e]/128
+};
+
+function check_member(s: subnet)
+	{
+	if ( s in testt )
+		print fmt("in says: %s is member", s);
+	else
+		print fmt("in says: %s is no member", s);
+
+	if ( check_subnet(s, testt) )
+		print fmt("check_subnet says: %s is member", s);
+	else
+		print fmt("check_subnet says: %s is no member", s);
+
+	}
+
+event bro_init()
+	{
+	check_member(10.2.0.2/32);
+	check_member(10.2.0.2/31);
+	check_member(10.6.0.0/9);
+	check_member(10.2.0.0/8);
+	}