patch-2.1.80 linux/include/asm-arm/checksum.h

• Lines: 155
• Date: Tue Jan 20 16:39:42 1998
• Orig file: v2.1.79/linux/include/asm-arm/checksum.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.79/linux/include/asm-arm/checksum.h linux/include/asm-arm/checksum.h
@@ -0,0 +1,154 @@
+/*
+ * linux/include/asm-arm/checksum.h
+ *
+ * IP checksum routines
+ *
+ * Copyright (C) Original authors of ../asm-i386/checksum.h
+ * Copyright (C) 1996,1997,1998 Russell King
+ */
+#ifndef __ASM_ARM_CHECKSUM_H
+#define __ASM_ARM_CHECKSUM_H
+
+#ifndef __ASM_ARM_SEGMENT_H
+#include <asm/segment.h>
+#endif
+
+/*
+ * 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);
+
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums, and handles user-space pointer exceptions correctly, when needed.
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+
+extern
+unsigned int csum_partial_copy_from_user (const char *src, char *dst, int len, int sum, int *err_ptr);
+
+/*
+ * This combination is currently not used, but possible:
+ */
+extern
+unsigned int csum_partial_copy_to_user (const char *src, char *dst, int len, int sum, int *err_ptr);
+
+/*
+ * These are the old (and unsafe) way of doing checksums, a warning message will be
+ * printed if they are used and an exception occurs.
+ *
+ * these functions should go away after some time.
+ */
+#define csum_partial_copy_fromuser csum_partial_copy
+unsigned int csum_partial_copy(const char *src, char *dst, int len, int sum);
+
+/*
+ *	This is a version of ip_compute_csum() optimized for IP headers,
+ *	which always checksum on 4 octet boundaries.
+ *
+ *	Converted and optimised for ARM by R. M. King.
+ *
+ *	Note: the order that the LDM registers are loaded with respect to
+ *	the adc's doesn't matter.
+ */
+static inline unsigned short ip_fast_csum(unsigned char * iph,
+					  unsigned int ihl) {
+	unsigned int sum, tmp1;
+
+    __asm__ __volatile__("
+	sub	%2, %2, #5
+	ldr	%0, [%1], #4
+	ldr	%3, [%1], #4
+	adds	%0, %0, %3
+	ldr	%3, [%1], #4
+	adcs	%0, %0, %3
+	ldr	%3, [%1], #4
+	adcs	%0, %0, %3
+1:	ldr	%3, [%1], #4
+	adcs	%0, %0, %3
+	tst	%2, #15
+	subne	%2, %2, #1
+	bne	1b
+	adc	%0, %0, #0
+	adds	%0, %0, %0, lsl #16
+	addcs	%0, %0, #0x10000
+	mvn	%0, %0
+	mov	%0, %0, lsr #16
+	"
+	: "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (tmp1)
+	: "1" (iph), "2" (ihl));
+	return(sum);
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
+						   unsigned long daddr,
+						   unsigned short len,
+						   unsigned short proto,
+						   unsigned int sum) {
+    __asm__ __volatile__("
+    adds	%0, %0, %1
+    adcs	%0, %0, %4
+    adcs	%0, %0, %5
+    adc		%0, %0, #0
+    adds	%0, %0, %0, lsl #16
+    addcs	%0, %0, #0x10000
+    mvn		%0, %0
+    mov		%0, %0, lsr #16
+	"
+	: "=&r" (sum), "=&r" (saddr)
+	: "0" (daddr), "1"(saddr), "r"((ntohs(len)<<16)+proto*256), "r"(sum));
+	return((unsigned short)sum);
+}
+
+/*
+ * 	Fold a partial checksum without adding pseudo headers
+ */
+static inline unsigned int csum_fold(unsigned int sum)
+{
+    __asm__ __volatile__("
+    adds	%0, %0, %0, lsl #16
+    addcs	%0, %0, #0x10000
+    mvn		%0, %0
+    mov		%0, %0, lsr #16
+	"
+	: "=r" (sum)
+	: "0" (sum));
+	return sum;
+}	
+	
+
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+
+static inline unsigned short ip_compute_csum(unsigned char * buff, int len) {
+    unsigned int sum;
+
+    __asm__ __volatile__("
+    adds	%0, %0, %0, lsl #16
+    addcs	%0, %0, #0x10000
+    mvn		%0, %0
+    mov		%0, %0, lsr #16
+	"
+	: "=r"(sum)
+	: "0" (csum_partial(buff, len, 0)));
+	return(sum);
+}
+
+#endif