patch-2.4.22 linux-2.4.22/include/linux/crc32.h

• Lines: 67
• Date: 2003-08-25 04:44:44.000000000 -0700
• Orig file: linux-2.4.21/include/linux/crc32.h
• Orig date: 2002-08-02 17:39:45.000000000 -0700

diff -urN linux-2.4.21/include/linux/crc32.h linux-2.4.22/include/linux/crc32.h
@@ -1,49 +1,27 @@
 /*
- * crc32.h for early Linux 2.4.19pre kernel inclusion
- * This defines ether_crc_le() and ether_crc() as inline functions
- * This is slated to change to using the library crc32 functions
- * as kernel 2.5.2 included at some future date.
+ * crc32.h
+ * See linux/lib/crc32.c for license and changes
  */
 #ifndef _LINUX_CRC32_H
 #define _LINUX_CRC32_H
 
 #include <linux/types.h>
 
-/* The little-endian AUTODIN II ethernet CRC calculation.
-   N.B. Do not use for bulk data, use a table-based routine instead.
-   This is common code and should be moved to net/core/crc.c */
-static unsigned const ethernet_polynomial_le = 0xedb88320U;
-static inline unsigned ether_crc_le(int length, unsigned char *data)
-{
-	unsigned int crc = 0xffffffff;	/* Initial value. */
-	while(--length >= 0) {
-		unsigned char current_octet = *data++;
-		int bit;
-		for (bit = 8; --bit >= 0; current_octet >>= 1) {
-			if ((crc ^ current_octet) & 1) {
-				crc >>= 1;
-				crc ^= ethernet_polynomial_le;
-			} else
-				crc >>= 1;
-		}
-	}
-	return crc;
-}
+extern u32  crc32_le(u32 crc, unsigned char const *p, size_t len);
+extern u32  crc32_be(u32 crc, unsigned char const *p, size_t len);
+extern u32  bitreverse(u32 in);
 
-static unsigned const ethernet_polynomial = 0x04c11db7U;
-static inline u32 ether_crc(int length, unsigned char *data)
-{
-	int crc = -1;
-	while (--length >= 0) {
-		unsigned char current_octet = *data++;
-		int bit;
-		for (bit = 0; bit < 8; bit++, current_octet >>= 1) {
-			crc = (crc << 1) ^
-				((crc < 0) ^ (current_octet & 1) ?
-				 ethernet_polynomial : 0);
-		}
-	}
-	return crc;
-}
+#define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)data, length)
+
+/*
+ * Helpers for hash table generation of ethernet nics:
+ *
+ * Ethernet sends the least significant bit of a byte first, thus crc32_le
+ * is used. The output of crc32_le is bit reversed [most significant bit
+ * is in bit nr 0], thus it must be reversed before use. Except for
+ * nics that bit swap the result internally...
+ */
+#define ether_crc(length, data)    bitreverse(crc32_le(~0, data, length))
+#define ether_crc_le(length, data) crc32_le(~0, data, length)
 
 #endif /* _LINUX_CRC32_H */