patch-2.4.20 linux-2.4.20/arch/x86_64/lib/csum-wrappers.c

• Lines: 110
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/x86_64/lib/csum-wrappers.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/x86_64/lib/csum-wrappers.c linux-2.4.20/arch/x86_64/lib/csum-wrappers.c
@@ -0,0 +1,109 @@
+/* Copyright 2002 Andi Kleen, SuSE Labs.
+ * Subject to the GNU Public License v.2
+ * 
+ * Wrappers of assembly checksum functions for x86-64.
+ */
+
+#include <asm/checksum.h>
+#include <linux/module.h>
+
+/* Better way for this sought */
+static inline unsigned from64to32(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);
+        return x;
+}
+
+/** 
+ * csum_partial_copy_from_user - Copy and checksum from user space. 
+ * @src: source address (user space) 
+ * @dst: destination address
+ * @len: number of bytes to be copied.
+ * @isum: initial sum that is added into the result (32bit unfolded)
+ * @errp: set to -EFAULT for an bad source address.
+ * 
+ * Returns an 32bit unfolded checksum of the buffer.
+ * src and dst are best aligned to 64bits. 
+ */ 
+unsigned int 
+csum_partial_copy_from_user(const char *src, char *dst, 
+			    int len, unsigned int isum, int *errp)
+{ 
+	*errp = 0;
+	if (likely(access_ok(VERIFY_READ,src, len))) { 
+		unsigned long sum; 
+		sum = csum_partial_copy_generic(src,dst,len,isum,errp,NULL);
+		if (likely(*errp == 0)) 
+			return from64to32(sum); 
+	} 
+	*errp = -EFAULT;
+	memset(dst,0,len); 
+	return 0;		
+} 
+
+EXPORT_SYMBOL(csum_partial_copy_from_user);
+
+/** 
+ * csum_partial_copy_to_user - Copy and checksum to user space. 
+ * @src: source address
+ * @dst: destination address (user space)
+ * @len: number of bytes to be copied.
+ * @isum: initial sum that is added into the result (32bit unfolded)
+ * @errp: set to -EFAULT for an bad destination address.
+ * 
+ * Returns an 32bit unfolded checksum of the buffer.
+ * src and dst are best aligned to 64bits.
+ */ 
+unsigned int 
+csum_partial_copy_to_user(const char *src, char *dst, 
+			  int len, unsigned int isum, int *errp)
+{ 
+	if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) {
+		*errp = -EFAULT;
+		return 0; 
+	}
+	*errp = 0;
+	return from64to32(csum_partial_copy_generic(src,dst,len,isum,NULL,errp)); 
+} 
+
+EXPORT_SYMBOL(csum_partial_copy_to_user);
+
+/** 
+ * csum_partial_copy_nocheck - Copy and checksum.
+ * @src: source address
+ * @dst: destination address
+ * @len: number of bytes to be copied.
+ * @isum: initial sum that is added into the result (32bit unfolded)
+ * 
+ * Returns an 32bit unfolded checksum of the buffer.
+ */ 
+unsigned int 
+csum_partial_copy_nocheck(const char *src, char *dst, int len, unsigned int sum)
+{ 
+	return from64to32(csum_partial_copy_generic(src,dst,len,sum,NULL,NULL));
+} 
+
+//EXPORT_SYMBOL(csum_partial_copy_nocheck);
+
+unsigned short csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
+			       __u32 len, unsigned short proto, unsigned int sum) 
+{
+	__u64 rest, sum64;
+     
+	rest = (__u64)htonl(len) + (__u64)htons(proto) + (__u64)sum;
+	asm("  addq (%[saddr]),%[sum]\n"
+	    "  adcq 8(%[saddr]),%[sum]\n"
+	    "  adcq (%[daddr]),%[sum]\n" 
+	    "  adcq 8(%[daddr]),%[sum]\n"
+	    "  adcq $0,%[sum]\n"
+	    : [sum] "=r" (sum64) 
+	    : "[sum]" (rest),[saddr] "r" (saddr), [daddr] "r" (daddr));
+	return csum_fold(from64to32(sum64)); 
+}
+
+EXPORT_SYMBOL(csum_ipv6_magic);