patch-2.3.99-pre8 linux/include/asm-s390/checksum.h

• Lines: 189
• Date: Fri May 12 11:41:44 2000
• Orig file: v2.3.99-pre7/linux/include/asm-s390/checksum.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.99-pre7/linux/include/asm-s390/checksum.h linux/include/asm-s390/checksum.h
@@ -0,0 +1,188 @@
+#ifndef _S390_CHECKSUM_H
+#define _S390_CHECKSUM_H
+
+/*
+ *  include/asm-s390/checksum.h
+ *    S390 fast network checksum routines
+ *    see also arch/S390/lib/checksum.c
+ *
+ *  S390 version
+ *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Author(s): Ulrich Hild        (first version)
+ *               Martin Schwidefsky (heavily optimized CKSM version)
+ *               D.J. Barrow        (third attempt) 
+ */
+
+#include <asm/uaccess.h>
+
+/*
+ * 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);
+
+/*
+ * csum_partial as an inline function
+ */
+extern inline unsigned int 
+csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
+{
+	__asm__ __volatile__ (
+		"    lr   2,%1\n"    /* address in gpr 2 */
+		"    lr   3,%2\n"    /* length in gpr 3 */
+		"0:  cksm %0,2\n"    /* do checksum on longs */
+		"    jo   0b\n"
+                : "+&d" (sum)
+		: "d" (buff), "d" (len)
+                : "cc", "2", "3" );
+	return sum;
+}
+
+/*
+ * the same as csum_partial, but copies from 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(const char *src, char *dst, int len,unsigned int sum)
+{
+	memcpy(dst,src,len);
+        return csum_partial_inline(dst, len, sum);
+}
+
+/*
+ * the same as csum_partial_copy, but copies from user space.
+ *
+ * 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_from_user(const char *src, char *dst,
+                            int len, unsigned int sum, int *errp)
+{
+	if (copy_from_user(dst, src, len)) {
+		*errp = -EFAULT;
+		memset(dst, 0, len);
+		return sum;
+        }
+        return csum_partial(dst, len, sum);
+}
+
+extern inline unsigned int
+csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
+{
+        memcpy(dst,src,len);
+        return csum_partial_inline(dst, len, sum);
+}
+
+/*
+ *      Fold a partial checksum without adding pseudo headers
+ */
+#if 1
+unsigned short csum_fold(unsigned int sum);
+#else
+extern inline unsigned short
+csum_fold(unsigned int sum)
+{
+	__asm__ __volatile__ (
+		"    sr   3,3\n"   /* %0 = H*65536 + L */
+		"    lr   2,%0\n"  /* %0 = H L, R2/R3 = H L / 0 0 */
+		"    srdl 2,16\n"  /* %0 = H L, R2/R3 = 0 H / L 0 */
+		"    alr  2,3\n"   /* %0 = H L, R2/R3 = L H / L 0 */
+		"    alr  %0,2\n"  /* %0 = H+L+C L+H */
+                "    srl  %0,16\n" /* %0 = H+L+C */
+		: "+&d" (sum) : : "cc", "2", "3");
+	return ((unsigned short) ~sum);
+}
+#endif
+
+/*
+ *	This is a version of ip_compute_csum() optimized for IP headers,
+ *	which always checksum on 4 octet boundaries.
+ *
+ */
+extern inline unsigned short
+ip_fast_csum(unsigned char *iph, unsigned int ihl)
+{
+	unsigned long sum;
+
+        __asm__ __volatile__ (
+		"    sr   %0,%0\n"   /* set sum to zero */
+                "    lr   2,%1\n"    /* address in gpr 2 */
+                "    lr   3,%2\n"    /* length in gpr 3 */
+                "0:  cksm %0,2\n"    /* do checksum on longs */
+                "    jo   0b\n"
+                : "=&d" (sum)
+                : "d" (iph), "d" (ihl*4)
+                : "cc", "2", "3" );
+        return csum_fold(sum);
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 32-bit checksum
+ */
+extern inline unsigned int 
+csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
+                   unsigned short len, unsigned short proto,
+                   unsigned int sum)
+{
+	__asm__ __volatile__ (
+		"    sll   %3,16\n"
+		"    or    %3,%4\n"  /* newproto=proto<<16 in hiword, len in lowword */
+		"    alr   %1,%2\n"  /* saddr+=daddr */
+		"    brc   12,0f\n"
+		"    ahi   %1,1\n"   /* add carry */
+		"0:  alr   %1,%3\n"  /* add saddr+=newproto */
+		"    brc   12,1f\n"
+		"    ahi   %1,1\n"   /* add carry again */
+		"1:  alr   %0,%1\n"  /* sum+=saddr */
+		"    brc   12,2f\n"
+		"    ahi   %0,1\n"   /* add carry again */
+		"2:"
+		: "+&d" (sum)
+		: "d" (saddr), "d" (daddr), "d" (proto), "d" (len)
+		: "cc" );
+	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 csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,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 csum_fold(csum_partial(buff, len, 0));
+}
+
+#endif /* _S390_CHECKSUM_H */
+
+