patch-2.3.43 linux/arch/ia64/lib/checksum.c

• Lines: 111
• Date: Sun Feb 6 18:42:40 2000
• Orig file: v2.3.42/linux/arch/ia64/lib/checksum.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.42/linux/arch/ia64/lib/checksum.c linux/arch/ia64/lib/checksum.c
@@ -0,0 +1,110 @@
+/*
+ * Network checksum routines
+ *
+ * Copyright (C) 1999 Hewlett-Packard Co
+ * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
+ *
+ * Most of the code coming from arch/alpha/lib/checksum.c
+ *
+ * This file contains network checksum routines that are better done
+ * in an architecture-specific manner due to speed..
+ */
+ 
+#include <linux/string.h>
+
+#include <asm/byteorder.h>
+
+static inline unsigned short
+from64to16(unsigned long x)
+{
+	/* add up 32-bit words for 33 bits */
+	x = (x & 0xffffffff) + (x >> 32);
+	/* add up 16-bit and 17-bit words for 17+c bits */
+	x = (x & 0xffff) + (x >> 16);
+	/* add up 16-bit and 2-bit for 16+c bit */
+	x = (x & 0xffff) + (x >> 16);
+	/* add up carry.. */
+	x = (x & 0xffff) + (x >> 16);
+	return x;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented.
+ */
+unsigned short int csum_tcpudp_magic(unsigned long saddr,
+				   unsigned long daddr,
+				   unsigned short len,
+				   unsigned short proto,
+				   unsigned int sum)
+{
+	return ~from64to16(saddr + daddr + sum +
+		((unsigned long) ntohs(len) << 16) +
+		((unsigned long) proto << 8));
+}
+
+unsigned int csum_tcpudp_nofold(unsigned long saddr,
+				   unsigned long daddr,
+				   unsigned short len,
+				   unsigned short proto,
+				   unsigned int sum)
+{
+	unsigned long result;
+
+	result = (saddr + daddr + sum +
+		  ((unsigned long) ntohs(len) << 16) +
+		  ((unsigned long) proto << 8));
+
+	/* Fold down to 32-bits so we don't loose in the typedef-less 
+	   network stack.  */
+	/* 64 to 33 */
+	result = (result & 0xffffffff) + (result >> 32);
+	/* 33 to 32 */
+	result = (result & 0xffffffff) + (result >> 32);
+	return result;
+}
+
+extern unsigned long do_csum(const unsigned char *, unsigned int, unsigned int);
+extern unsigned long do_csum_c(const unsigned char *, unsigned int, unsigned int);
+
+/*
+ *	This is a version of ip_compute_csum() optimized for IP headers,
+ *	which always checksum on 4 octet boundaries.
+ */
+unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
+{
+	return ~do_csum(iph,ihl*4,0);
+}
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
+{
+	unsigned long result = do_csum(buff, len, 0);
+
+	/* add in old sum, and carry.. */
+	result += sum;
+	/* 32+c bits -> 32 bits */
+	result = (result & 0xffffffff) + (result >> 32);
+	return result;
+}
+
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+unsigned short ip_compute_csum(unsigned char * buff, int len)
+{
+	return ~do_csum(buff,len, 0);
+}