drouting: fix crush for empty username in ruri

- uri like sip:@host crushed kamailio (cherry picked from commit e4f3849)
kamailio · Aug 23, 2018 · 7ab0b1c · 7ab0b1c
1 parent 5b31b87
commit 7ab0b1c
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/src/modules/drouting/prefix_tree.c b/src/modules/drouting/prefix_tree.c
@@ -115,7 +115,7 @@ get_prefix(
 
 	if(NULL == ptree)
 		goto err_exit;
-	if(NULL == prefix)
+	if(NULL == prefix || NULL == prefix->s)
 		goto err_exit;
 	tmp = prefix->s;
 	/* go the tree down to the last digit in the