patch-1.3.44 linux/include/asm-sparc/checksum.h

• Lines: 163
• Date: Sat Nov 25 04:31:24 1995
• Orig file: v1.3.43/linux/include/asm-sparc/checksum.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.43/linux/include/asm-sparc/checksum.h linux/include/asm-sparc/checksum.h
@@ -0,0 +1,162 @@
+/* $Id: checksum.h,v 1.10 1995/11/25 02:31:23 davem Exp $ */
+#ifndef __SPARC_CHECKSUM_H
+#define __SPARC_CHECKSUM_H
+
+/*  checksum.h:  IP/UDP/TCP checksum routines on the Sparc.
+ *
+ *  Copyright(C) 1995 Linus Torvalds
+ *  Copyright(C) 1995 Miguel de Icaza
+ */
+
+
+/* 32 bits version of the checksum routines written for the Alpha by Linus */
+extern inline unsigned short from32to16(unsigned long x)
+{
+	/* 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;
+}
+
+extern inline unsigned long
+do_csum(unsigned char * buff, int len)
+{
+	int odd, count;
+	unsigned long result = 0;
+
+	if (len <= 0)
+		goto out;
+	odd = 1 & (unsigned long) buff;
+	if (odd) {
+		result = *buff << 8;
+		len--;
+		buff++;
+	}
+	count = len >> 1;		/* nr of 16-bit words.. */
+	if (count) {
+		if (2 & (unsigned long) buff) {
+			result += *(unsigned short *) buff;
+			count--;
+			len -= 2;
+			buff += 2;
+		}
+		count >>= 1;		/* nr of 32-bit words.. */
+		if (count) {
+		        unsigned long carry = 0;
+			do {
+				unsigned long w = *(unsigned long *) buff;
+				count--;
+				buff += 4;
+				len -= 4;
+				result += carry;
+				result += w;
+				carry = (w > result);
+			} while (count);
+			result += carry;
+			result = (result & 0xffff) + (result >> 16);
+		}
+		if (len & 2) {
+			result += *(unsigned short *) buff;
+			buff += 2;
+		}
+	}
+	if (len & 1)
+		result += (*buff) << 8;
+	result = from32to16(result);
+	if (odd)
+		result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
+out:
+	return result;
+}
+
+extern inline unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl)
+{
+	return ~do_csum(iph,ihl*4);
+}
+
+/*
+ * 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
+ */
+extern inline unsigned int csum_partial(unsigned char * buff, int len, unsigned int sum)
+{
+	unsigned long result = do_csum(buff, len);
+
+	/* add in old sum, and carry.. */
+	result += sum;
+	/* 32+c bits -> 32 bits */
+	result = (result & 0xffff) + (result >> 16);
+	return result;
+}
+
+/*
+ * the same as csum_partial, but copies from fs:src while it
+ * checksums
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+extern inline unsigned int csum_partial_copy(char *src, char *dst, int len, int sum)
+{
+	/*
+	 * The whole idea is to do the copy and the checksum at
+	 * the same time, but we do it the easy way now.
+	 *
+	 * At least csum on the source, not destination, for cache
+	 * reasons..
+	 */
+	sum = csum_partial(src, len, sum);
+	memcpy(dst, src, len);
+	return sum;
+}
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+extern inline unsigned short ip_compute_csum(unsigned char * buff, int len)
+{
+	return ~from32to16(do_csum(buff,len));
+}
+
+#define csum_partial_copy_fromuser(s, d, l, w)  \
+                       csum_partial_copy((char *) (s), (d), (l), (w))
+
+/*
+ *	Fold a partial checksum without adding pseudo headers
+ */
+
+static inline unsigned short csum_fold(unsigned int sum)
+{
+	sum = (sum & 0xffff) + (sum >> 16);
+	sum = (sum & 0xffff) + (sum >> 16);
+	return ~sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
+					   unsigned long daddr,
+					   unsigned short len,
+					   unsigned short proto,
+					   unsigned int sum)
+{
+	return ~from32to16 (((saddr >> 16) + (saddr & 0xffff) + (daddr >> 16)
+			     + (daddr & 0xffff) + (sum >> 16) +
+			     (sum & 0xffff) + proto + len));
+}
+
+#endif /* !(__SPARC_CHECKSUM_H) */