git://bbs.cooldavid.org / net-next-2.6.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
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. | |
| 5 | * | |
| 6 | * Checksumming functions for IP, TCP, UDP and so on | |
| 7 | * | |
| 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. | |
| 12 | * | |
| 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. | |
| 17 | */ | |
| 18 | ||
| 19 | #ifndef _CHECKSUM_H | |
| 20 | #define _CHECKSUM_H | |
| 21 | ||
| 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> | |
| 27 | ||
| 28 | #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER | |
| 29 | static inline | |
| 30 | unsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst, | |
| 31 | int len, int sum, int *err_ptr) | |
| 32 | { | |
| 33 | if (access_ok(VERIFY_READ, src, len)) | |
| 34 | return csum_partial_copy_from_user(src, dst, len, sum, err_ptr); | |
| 35 | ||
| 36 | if (len) | |
| 37 | *err_ptr = -EFAULT; | |
| 38 | ||
| 39 | return sum; | |
| 40 | } | |
| 41 | #endif | |
| 42 | ||
| 43 | #ifndef HAVE_CSUM_COPY_USER | |
| 44 | static __inline__ unsigned int csum_and_copy_to_user | |
| 45 | (const unsigned char *src, unsigned char __user *dst, int len, unsigned int sum, int *err_ptr) | |
| 46 | { | |
| 47 | sum = csum_partial(src, len, sum); | |
| 48 | ||
| 49 | if (access_ok(VERIFY_WRITE, dst, len)) { | |
| 50 | if (copy_to_user(dst, src, len) == 0) | |
| 51 | return sum; | |
| 52 | } | |
| 53 | if (len) | |
| 54 | *err_ptr = -EFAULT; | |
| 55 | ||
| 56 | return -1; /* invalid checksum */ | |
| 57 | } | |
| 58 | #endif | |
| 59 | ||
| 60 | static inline unsigned int csum_add(unsigned int csum, unsigned int addend) | |
| 61 | { | |
| 62 | csum += addend; | |
| 63 | return csum + (csum < addend); | |
| 64 | } | |
| 65 | ||
| 66 | static inline unsigned int csum_sub(unsigned int csum, unsigned int addend) | |
| 67 | { | |
| 68 | return csum_add(csum, ~addend); | |
| 69 | } | |
| 70 | ||
| 71 | static inline unsigned int | |
| 72 | csum_block_add(unsigned int csum, unsigned int csum2, int offset) | |
| 73 | { | |
| 74 | if (offset&1) | |
| 75 | csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF); | |
| 76 | return csum_add(csum, csum2); | |
| 77 | } | |
| 78 | ||
| 79 | static inline unsigned int | |
| 80 | csum_block_sub(unsigned int csum, unsigned int csum2, int offset) | |
| 81 | { | |
| 82 | if (offset&1) | |
| 83 | csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF); | |
| 84 | return csum_sub(csum, csum2); | |
| 85 | } | |
| 86 | ||
| 87 | #endif |