/* * 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 unsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst, int len, int 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__ unsigned int csum_and_copy_to_user (const unsigned char *src, unsigned char __user *dst, int len, unsigned int 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 -1; /* invalid checksum */ } #endif static inline unsigned int csum_add(unsigned int csum, unsigned int addend) { csum += addend; return csum + (csum < addend); } static inline unsigned int csum_sub(unsigned int csum, unsigned int addend) { return csum_add(csum, ~addend); } static inline unsigned int csum_block_add(unsigned int csum, unsigned int csum2, int offset) { if (offset&1) csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF); return csum_add(csum, csum2); } static inline unsigned int csum_block_sub(unsigned int csum, unsigned int csum2, int offset) { if (offset&1) csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF); return csum_sub(csum, csum2); } #endif