1 files changed, 5 insertions, 0 deletions
diff --git a/checksum.h b/checksum.h
index 0212923..377e38d 100644
--- a/checksum.h
+++ b/checksum.h
@@ -3,8 +3,13 @@
  * Author: Stefano Brivio <sbrivio@redhat.com>
  */
 
+#ifndef CHECKSUM_H
+#define CHECKSUM_H
+
 uint32_t sum_16b(void *buf, size_t len);
 uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(void *buf, size_t len, uint32_t init);
 void csum_tcp4(struct iphdr *iph);
 uint16_t csum(const void *buf, size_t len, uint32_t init);
+
+#endif /* CHECKSUM_H */