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 __asm__ __volatile__ ( 40 " lgr 2,%1\n" /* address in gpr 2 */ 41 " lgfr 3,%2\n" /* length in gpr 3 */ 42 "0: cksm %0,2\n" /* do checksum on longs */ 43 " jo 0b\n" 44 : "+&d" (sum) 45 : "d" (buff), "d" (len) 46 : "cc", "2", "3" ); 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 90extern inline unsigned int 91csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum) 92{ 93 memcpy(dst,src,len); 94 return csum_partial_inline(dst, len, sum); 95} 96 97/* 98 * Fold a partial checksum without adding pseudo headers 99 */ 100extern inline unsigned short 101csum_fold(unsigned int sum) 102{ 103 __asm__ __volatile__ ( 104 " sr 3,3\n" /* %0 = H*65536 + L */ 105 " lr 2,%0\n" /* %0 = H L, R2/R3 = H L / 0 0 */ 106 " srdl 2,16\n" /* %0 = H L, R2/R3 = 0 H / L 0 */ 107 " alr 2,3\n" /* %0 = H L, R2/R3 = L H / L 0 */ 108 " alr %0,2\n" /* %0 = H+L+C L+H */ 109 " srl %0,16\n" /* %0 = H+L+C */ 110 : "+&d" (sum) : : "cc", "2", "3"); 111 return ((unsigned short) ~sum); 112} 113 114/* 115 * This is a version of ip_compute_csum() optimized for IP headers, 116 * which always checksum on 4 octet boundaries. 117 * 118 */ 119extern inline unsigned short 120ip_fast_csum(unsigned char *iph, unsigned int ihl) 121{ 122 unsigned long sum; 123 124 __asm__ __volatile__ ( 125 " slgr %0,%0\n" /* set sum to zero */ 126 " lgr 2,%1\n" /* address in gpr 2 */ 127 " lgfr 3,%2\n" /* length in gpr 3 */ 128 "0: cksm %0,2\n" /* do checksum on ints */ 129 " jo 0b\n" 130 : "=&d" (sum) 131 : "d" (iph), "d" (ihl*4) 132 : "cc", "2", "3" ); 133 return csum_fold(sum); 134} 135 136/* 137 * computes the checksum of the TCP/UDP pseudo-header 138 * returns a 32-bit checksum 139 */ 140extern inline unsigned int 141csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, 142 unsigned short len, unsigned short proto, 143 unsigned int sum) 144{ 145 __asm__ __volatile__ ( 146 " lgfr %0,%0\n" 147 " algr %0,%1\n" /* sum += saddr */ 148 " brc 12,0f\n" 149 " aghi %0,1\n" /* add carry */ 150 "0: algr %0,%2\n" /* sum += daddr */ 151 " brc 12,1f\n" 152 " aghi %0,1\n" /* add carry */ 153 "1: algfr %0,%3\n" /* sum += (len<<16) + proto */ 154 " brc 12,2f\n" 155 " aghi %0,1\n" /* add carry */ 156 "2: srlg 0,%0,32\n" 157 " alr %0,0\n" /* fold to 32 bits */ 158 " brc 12,3f\n" 159 " ahi %0,1\n" /* add carry */ 160 "3: llgfr %0,%0" 161 : "+&d" (sum) 162 : "d" (saddr), "d" (daddr), 163 "d" (((unsigned int) len<<16) + (unsigned int) proto) 164 : "cc", "0" ); 165 return sum; 166} 167 168/* 169 * computes the checksum of the TCP/UDP pseudo-header 170 * returns a 16-bit checksum, already complemented 171 */ 172 173extern inline unsigned short int 174csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, 175 unsigned short len, unsigned short proto, 176 unsigned int sum) 177{ 178 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); 179} 180 181/* 182 * this routine is used for miscellaneous IP-like checksums, mainly 183 * in icmp.c 184 */ 185 186extern inline unsigned short 187ip_compute_csum(unsigned char * buff, int len) 188{ 189 return csum_fold(csum_partial_inline(buff, len, 0)); 190} 191 192#endif /* _S390_CHECKSUM_H */ 193 194 195