libata-link: separate out link initialization functions
[pv_ops_mirror.git] / include / net / checksum.h
blob124246172a88990ba6e04c1c7315a4e09f81ce0a
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * Checksumming functions for IP, TCP, UDP and so on
8 * Authors: Jorge Cwik, <jorge@laser.satlink.net>
9 * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
10 * Borrows very liberally from tcp.c and ip.c, see those
11 * files for more names.
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
19 #ifndef _CHECKSUM_H
20 #define _CHECKSUM_H
22 #include <linux/errno.h>
23 #include <asm/types.h>
24 #include <asm/byteorder.h>
25 #include <asm/uaccess.h>
26 #include <asm/checksum.h>
28 #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
29 static inline
30 __wsum csum_and_copy_from_user (const void __user *src, void *dst,
31 int len, __wsum sum, int *err_ptr)
33 if (access_ok(VERIFY_READ, src, len))
34 return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
36 if (len)
37 *err_ptr = -EFAULT;
39 return sum;
41 #endif
43 #ifndef HAVE_CSUM_COPY_USER
44 static __inline__ __wsum csum_and_copy_to_user
45 (const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
47 sum = csum_partial(src, len, sum);
49 if (access_ok(VERIFY_WRITE, dst, len)) {
50 if (copy_to_user(dst, src, len) == 0)
51 return sum;
53 if (len)
54 *err_ptr = -EFAULT;
56 return (__force __wsum)-1; /* invalid checksum */
58 #endif
60 static inline __wsum csum_add(__wsum csum, __wsum addend)
62 u32 res = (__force u32)csum;
63 res += (__force u32)addend;
64 return (__force __wsum)(res + (res < (__force u32)addend));
67 static inline __wsum csum_sub(__wsum csum, __wsum addend)
69 return csum_add(csum, ~addend);
72 static inline __wsum
73 csum_block_add(__wsum csum, __wsum csum2, int offset)
75 u32 sum = (__force u32)csum2;
76 if (offset&1)
77 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
78 return csum_add(csum, (__force __wsum)sum);
81 static inline __wsum
82 csum_block_sub(__wsum csum, __wsum csum2, int offset)
84 u32 sum = (__force u32)csum2;
85 if (offset&1)
86 sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
87 return csum_sub(csum, (__force __wsum)sum);
90 static inline __wsum csum_unfold(__sum16 n)
92 return (__force __wsum)n;
95 #define CSUM_MANGLED_0 ((__force __sum16)0xffff)
96 #endif