1#ifndef _PPC64_CHECKSUM_H 2#define _PPC64_CHECKSUM_H 3 4/* 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License 7 * as published by the Free Software Foundation; either version 8 * 2 of the License, or (at your option) any later version. 9 */ 10 11/* 12 * This is a version of ip_compute_csum() optimized for IP headers, 13 * which always checksum on 4 octet boundaries. ihl is the number 14 * of 32-bit words and is always >= 5. 15 */ 16extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); 17 18/* 19 * computes the checksum of the TCP/UDP pseudo-header 20 * returns a 16-bit checksum, already complemented 21 */ 22extern unsigned short csum_tcpudp_magic(unsigned long saddr, 23 unsigned long daddr, 24 unsigned short len, 25 unsigned short proto, 26 unsigned int sum); 27 28/* 29 * computes the checksum of a memory block at buff, length len, 30 * and adds in "sum" (32-bit) 31 * 32 * returns a 32-bit number suitable for feeding into itself 33 * or csum_tcpudp_magic 34 * 35 * this function must be called with even lengths, except 36 * for the last fragment, which may be odd 37 * 38 * it's best to have buff aligned on a 32-bit boundary 39 */ 40extern unsigned int csum_partial(const unsigned char * buff, int len, 41 unsigned int sum); 42 43/* 44 * the same as csum_partial, but copies from src to dst while it 45 * checksums 46 */ 47unsigned int csum_partial_copy(const char *src, char *dst, 48 int len, unsigned int sum); 49 50extern unsigned int csum_partial_copy_generic(const char *src, char *dst, 51 int len, unsigned int sum, 52 int *src_err, int *dst_err); 53/* 54 * the same as csum_partial, but copies from user space. 55 */ 56 57unsigned int csum_partial_copy_fromuser(const char *src, 58 char *dst, 59 int len, 60 unsigned int sum, 61 int *src_err); 62 63unsigned int csum_partial_copy_nocheck(const char *src, 64 char *dst, 65 int len, 66 unsigned int sum); 67 68/* 69 * turns a 32-bit partial checksum (e.g. from csum_partial) into a 70 * 1's complement 16-bit checksum. 71 */ 72static inline unsigned int csum_fold(unsigned int sum) 73{ 74 unsigned int tmp; 75 76 /* swap the two 16-bit halves of sum */ 77 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); 78 /* if there is a carry from adding the two 16-bit halves, 79 it will carry from the lower half into the upper half, 80 giving us the correct sum in the upper half. */ 81 sum = ~(sum + tmp) >> 16; 82 return sum; 83} 84 85/* 86 * this routine is used for miscellaneous IP-like checksums, mainly 87 * in icmp.c 88 */ 89static inline unsigned short ip_compute_csum(unsigned char * buff, int len) 90{ 91 return csum_fold(csum_partial(buff, len, 0)); 92} 93 94#define csum_partial_copy_from_user(src, dst, len, sum, errp) \ 95 csum_partial_copy_generic((src), (dst), (len), (sum), (errp), 0) 96 97#define csum_partial_copy_nocheck(src, dst, len, sum) \ 98 csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0) 99 100static inline u32 csum_tcpudp_nofold(u32 saddr, 101 u32 daddr, 102 unsigned short len, 103 unsigned short proto, 104 unsigned int sum) 105{ 106 unsigned long s = sum; 107 108 s += saddr; 109 s += daddr; 110 s += (proto << 16) + len; 111 s += (s >> 32); 112 return (u32) s; 113} 114 115#endif 116