src: add assertion infrastructure to validate attribute types

This will be used to validate that the size is correct according
to the expected attribute size.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 20 insertions, 0 deletions

diff --git a/src/internal.h b/src/internal.h
index a3fc46f..3216bc6 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -187,4 +187,17 @@ struct nft_set_elem {
 
 #define __init __attribute__((constructor))
 
+void __nft_assert_fail(uint16_t attr, const char *filename, int line);
+
+#define nft_assert(attr, expr)				\
+  ((expr)						\
+   ? (void)0						\
+   : __nft_assert_fail(attr, __FILE__, __LINE__))
+
+#define nft_assert_validate(_validate_array, _attr, _data_len)		\
+({									\
+	if (_validate_array[_attr])					\
+		nft_assert(attr, _validate_array[_attr] == _data_len);	\
+})
+
 #endif
diff --git a/src/utils.c b/src/utils.c
index 9691c4c..18917f5 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -211,3 +211,10 @@ int nft_fprintf(FILE *fp, void *obj, uint32_t type, uint32_t flags,
 
 	return ret;
 }
+
+void __nft_assert_fail(uint16_t attr, const char *filename, int line)
+{
+	fprintf(stderr, "libnftnl: attribute %d assertion failed in %s:%d\n",
+		attr, filename, line);
+	exit(EXIT_FAILURE);
+}