adding crc16 to gnunet_crypto_lib.h

1 files changed, 34 insertions, 0 deletions

diff --git a/src/include/gnunet_crypto_lib.h b/src/include/gnunet_crypto_lib.h
index 76806d432..0be9611ba 100644
--- a/src/include/gnunet_crypto_lib.h
+++ b/src/include/gnunet_crypto_lib.h
@@ -233,6 +233,40 @@ struct GNUNET_CRYPTO_AuthKey
 void
 GNUNET_CRYPTO_seed_weak_random (int32_t seed);
 
+
+/**
+ * Perform an incremental step in a CRC16 (for TCP/IP) calculation.
+ *
+ * @param sum current sum, initially 0
+ * @param hdr buffer to calculate CRC over (must be 16-bit aligned)
+ * @param len number of bytes in hdr, must be multiple of 2
+ * @return updated crc sum (must be subjected to GNUNET_CRYPTO_crc16_finish to get actual crc16)
+ */
+uint32_t
+GNUNET_CRYPTO_crc16_step (uint32_t sum, uint16_t * hdr, size_t len);
+
+
+/**
+ * Convert results from GNUNET_CRYPTO_crc16_step to final crc16.
+ *
+ * @param sum cummulative sum
+ * @return crc16 value
+ */
+uint16_t
+GNUNET_CRYPTO_crc16_finish (uint32_t sum);
+
+
+/**
+ * Calculate the checksum of a buffer in one step.
+ *
+ * @param hdr buffer to  calculate CRC over (must be 16-bit aligned)
+ * @param len number of bytes in hdr, must be multiple of 2
+ * @return crc16 value
+ */
+uint16_t
+GNUNET_CRYPTO_crc16_n (uint16_t *hdr, size_t len);
+
+
 /**
  * Compute the CRC32 checksum for the first len
  * bytes of the buffer.