1#ifndef _S390_CHECKSUM_H 2#define _S390_CHECKSUM_H 3 4/* 5 * include/asm-s390/checksum.h 6 * S390 fast network checksum routines 7 * see also arch/S390/lib/checksum.c 8 * 9 * S390 version 10 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation 11 * Author(s): Ulrich Hild (first version) 12 * Martin Schwidefsky (heavily optimized CKSM version) 13 * D.J. Barrow (third attempt) 14 */ 15 16#include <asm/uaccess.h> 17 18/* 19 * computes the checksum of a memory block at buff, length len, 20 * and adds in "sum" (32-bit) 21 * 22 * returns a 32-bit number suitable for feeding into itself 23 * or csum_tcpudp_magic 24 * 25 * this function must be called with even lengths, except 26 * for the last fragment, which may be odd 27 * 28 * it's best to have buff aligned on a 32-bit boundary 29 */ 30unsigned int 31csum_partial(const unsigned char * buff, int len, unsigned int sum); 32 33/* 34 * csum_partial as an inline function 35 */ 36extern inline unsigned int 37csum_partial_inline(const unsigned char * buff, int len, unsigned int sum) 38{ 39 register_pair rp; 40 41 rp.subreg.even = (unsigned long) buff; 42 rp.subreg.odd = (unsigned long) len; 43 __asm__ __volatile__ ( 44 "0: cksm %0,%1\n" /* do checksum on longs */ 45 " jo 0b\n" 46 : "+&d" (sum), "+&a" (rp) : : "cc" ); 47 return sum; 48} 49 50/* 51 * the same as csum_partial, but copies from src while it 52 * checksums 53 * 54 * here even more important to align src and dst on a 32-bit (or even 55 * better 64-bit) boundary 56 */ 57 58extern inline unsigned int 59csum_partial_copy(const char *src, char *dst, int len,unsigned int sum) 60{ 61 memcpy(dst,src,len); 62 return csum_partial_inline(dst, len, sum); 63} 64 65/* 66 * the same as csum_partial_copy, but copies from user space. 67 * 68 * here even more important to align src and dst on a 32-bit (or even 69 * better 64-bit) boundary 70 * 71 * Copy from userspace and compute checksum. If we catch an exception 72 * then zero the rest of the buffer. 73 */ 74extern inline unsigned int 75csum_partial_copy_from_user (const char *src, char *dst, 76 int len, unsigned int sum, 77 int *err_ptr) 78{ 79 int missing; 80 81 missing = copy_from_user(dst, src, len); 82 if (missing) { 83 memset(dst + len - missing, 0, missing); 84 *err_ptr = -EFAULT; 85 } 86 87 return csum_partial(dst, len, sum); 88} 89 90 91extern inline unsigned int 92csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum) 93{ 94 memcpy(dst,src,len); 95 return csum_partial_inline(dst, len, sum); 96} 97 98/* 99 * Fold a partial checksum without adding pseudo headers 100 */ 101unsigned short csum_fold(unsigned int sum); 102 103/* 104 * This is a version of ip_compute_csum() optimized for IP headers, 105 * which always checksum on 4 octet boundaries. 106 * 107 */ 108extern inline unsigned short 109ip_fast_csum(unsigned char *iph, unsigned int ihl) 110{ 111 register_pair rp; 112 unsigned long sum; 113 114 rp.subreg.even = (unsigned long) iph; 115 rp.subreg.odd = (unsigned long) ihl*4; 116 __asm__ __volatile__ ( 117 " sr %0,%0\n" /* set sum to zero */ 118 "0: cksm %0,%1\n" /* do checksum on longs */ 119 " jo 0b\n" 120 : "=&d" (sum), "+&a" (rp) : : "cc" ); 121 return csum_fold(sum); 122} 123 124/* 125 * computes the checksum of the TCP/UDP pseudo-header 126 * returns a 32-bit checksum 127 */ 128extern inline unsigned int 129csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, 130 unsigned short len, unsigned short proto, 131 unsigned int sum) 132{ 133 __asm__ __volatile__ ( 134 " alr %0,%1\n" /* sum += saddr */ 135 " brc 12,0f\n" 136 " ahi %0,1\n" /* add carry */ 137 "0:" 138 : "+&d" (sum) : "d" (saddr) : "cc" ); 139 __asm__ __volatile__ ( 140 " alr %0,%1\n" /* sum += daddr */ 141 " brc 12,1f\n" 142 " ahi %0,1\n" /* add carry */ 143 "1:" 144 : "+&d" (sum) : "d" (daddr) : "cc" ); 145 __asm__ __volatile__ ( 146 " alr %0,%1\n" /* sum += (len<<16) + (proto<<8) */ 147 " brc 12,2f\n" 148 " ahi %0,1\n" /* add carry */ 149 "2:" 150 : "+&d" (sum) 151 : "d" (((unsigned int) len<<16) + (unsigned int) proto) 152 : "cc" ); 153 return sum; 154} 155 156/* 157 * computes the checksum of the TCP/UDP pseudo-header 158 * returns a 16-bit checksum, already complemented 159 */ 160 161extern inline unsigned short int 162csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, 163 unsigned short len, unsigned short proto, 164 unsigned int sum) 165{ 166 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); 167} 168 169/* 170 * this routine is used for miscellaneous IP-like checksums, mainly 171 * in icmp.c 172 */ 173 174extern inline unsigned short 175ip_compute_csum(unsigned char * buff, int len) 176{ 177 return csum_fold(csum_partial(buff, len, 0)); 178} 179 180#endif /* _S390_CHECKSUM_H */ 181 182 183