Initial import

1 files changed, 175 insertions, 0 deletions

diff --git a/include/net/checksum.h b/include/net/checksum.h
new file mode 100644
index 000000000..0a55ac715
--- /dev/null
+++ b/include/net/checksum.h
@@ -0,0 +1,175 @@
+/*
+ * INET		An implementation of the TCP/IP protocol suite for the LINUX
+ *		operating system.  INET is implemented using the  BSD Socket
+ *		interface as the means of communication with the user level.
+ *
+ *		Checksumming functions for IP, TCP, UDP and so on
+ *
+ * Authors:	Jorge Cwik, <jorge@laser.satlink.net>
+ *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
+ *		Borrows very liberally from tcp.c and ip.c, see those
+ *		files for more names.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _CHECKSUM_H
+#define _CHECKSUM_H
+
+#include <linux/errno.h>
+#include <asm/types.h>
+#include <asm/byteorder.h>
+#include <asm/uaccess.h>
+#include <asm/checksum.h>
+
+#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
+static inline
+__wsum csum_and_copy_from_user (const void __user *src, void *dst,
+				      int len, __wsum sum, int *err_ptr)
+{
+	if (access_ok(VERIFY_READ, src, len))
+		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
+
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return sum;
+}
+#endif
+
+#ifndef HAVE_CSUM_COPY_USER
+static __inline__ __wsum csum_and_copy_to_user
+(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
+{
+	sum = csum_partial(src, len, sum);
+
+	if (access_ok(VERIFY_WRITE, dst, len)) {
+		if (copy_to_user(dst, src, len) == 0)
+			return sum;
+	}
+	if (len)
+		*err_ptr = -EFAULT;
+
+	return (__force __wsum)-1; /* invalid checksum */
+}
+#endif
+
+#ifndef HAVE_ARCH_CSUM_ADD
+static inline __wsum csum_add(__wsum csum, __wsum addend)
+{
+	u32 res = (__force u32)csum;
+	res += (__force u32)addend;
+	return (__force __wsum)(res + (res < (__force u32)addend));
+}
+#endif
+
+static inline __wsum csum_sub(__wsum csum, __wsum addend)
+{
+	return csum_add(csum, ~addend);
+}
+
+static inline __sum16 csum16_add(__sum16 csum, __be16 addend)
+{
+	u16 res = (__force u16)csum;
+
+	res += (__force u16)addend;
+	return (__force __sum16)(res + (res < (__force u16)addend));
+}
+
+static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
+{
+	return csum16_add(csum, ~addend);
+}
+
+static inline __wsum
+csum_block_add(__wsum csum, __wsum csum2, int offset)
+{
+	u32 sum = (__force u32)csum2;
+	if (offset&1)
+		sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
+	return csum_add(csum, (__force __wsum)sum);
+}
+
+static inline __wsum
+csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
+{
+	return csum_block_add(csum, csum2, offset);
+}
+
+static inline __wsum
+csum_block_sub(__wsum csum, __wsum csum2, int offset)
+{
+	u32 sum = (__force u32)csum2;
+	if (offset&1)
+		sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
+	return csum_sub(csum, (__force __wsum)sum);
+}
+
+static inline __wsum csum_unfold(__sum16 n)
+{
+	return (__force __wsum)n;
+}
+
+static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
+{
+	return csum_partial(buff, len, sum);
+}
+
+#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
+
+static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
+{
+	*sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from), to));
+}
+
+/* Implements RFC 1624 (Incremental Internet Checksum)
+ * 3. Discussion states :
+ *     HC' = ~(~HC + ~m + m')
+ *  m : old value of a 16bit field
+ *  m' : new value of a 16bit field
+ */
+static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
+{
+	*sum = ~csum16_add(csum16_sub(~(*sum), old), new);
+}
+
+struct sk_buff;
+void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
+			      __be32 from, __be32 to, int pseudohdr);
+void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
+			       const __be32 *from, const __be32 *to,
+			       int pseudohdr);
+
+static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
+					    __be16 from, __be16 to,
+					    int pseudohdr)
+{
+	inet_proto_csum_replace4(sum, skb, (__force __be32)from,
+				 (__force __be32)to, pseudohdr);
+}
+
+static inline __wsum remcsum_adjust(void *ptr, __wsum csum,
+				    int start, int offset)
+{
+	__sum16 *psum = (__sum16 *)(ptr + offset);
+	__wsum delta;
+
+	/* Subtract out checksum up to start */
+	csum = csum_sub(csum, csum_partial(ptr, start, 0));
+
+	/* Set derived checksum in packet */
+	delta = csum_sub(csum_fold(csum), *psum);
+	*psum = csum_fold(csum);
+
+	return delta;
+}
+
+static inline void remcsum_unadjust(__sum16 *psum, __wsum delta)
+{
+	*psum = csum_fold(csum_sub(delta, *psum));
+}
+
+#endif