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-rw-r--r--include/net/checksum.h175
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