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 */ 30 static inline __wsum 31 csum_partial(const void *buff, int len, __wsum sum) 32 { 33 register unsigned long reg2 asm("2") = (unsigned long) buff; 34 register unsigned long reg3 asm("3") = (unsigned long) len; 35 36 asm volatile( 37 "0: cksm %0,%1\n" /* do checksum on longs */ 38 " jo 0b\n" 39 : "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory"); 40 return sum; 41 } 42 43 /* 44 * the same as csum_partial_copy, but copies from user space. 45 * 46 * here even more important to align src and dst on a 32-bit (or even 47 * better 64-bit) boundary 48 * 49 * Copy from userspace and compute checksum. If we catch an exception 50 * then zero the rest of the buffer. 51 */ 52 static inline __wsum 53 csum_partial_copy_from_user(const void __user *src, void *dst, 54 int len, __wsum sum, 55 int *err_ptr) 56 { 57 int missing; 58 59 missing = copy_from_user(dst, src, len); 60 if (missing) { 61 memset(dst + len - missing, 0, missing); 62 *err_ptr = -EFAULT; 63 } 64 65 return csum_partial(dst, len, sum); 66 } 67 68 69 static inline __wsum 70 csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum) 71 { 72 memcpy(dst,src,len); 73 return csum_partial(dst, len, sum); 74 } 75 76 /* 77 * Fold a partial checksum without adding pseudo headers 78 */ 79 static inline __sum16 csum_fold(__wsum sum) 80 { 81 u32 csum = (__force u32) sum; 82 83 csum += (csum >> 16) + (csum << 16); 84 csum >>= 16; 85 return (__force __sum16) ~csum; 86 } 87 88 /* 89 * This is a version of ip_compute_csum() optimized for IP headers, 90 * which always checksum on 4 octet boundaries. 91 * 92 */ 93 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 94 { 95 return csum_fold(csum_partial(iph, ihl*4, 0)); 96 } 97 98 /* 99 * computes the checksum of the TCP/UDP pseudo-header 100 * returns a 32-bit checksum 101 */ 102 static inline __wsum 103 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 104 unsigned short len, unsigned short proto, 105 __wsum sum) 106 { 107 __u32 csum = (__force __u32)sum; 108 109 csum += (__force __u32)saddr; 110 if (csum < (__force __u32)saddr) 111 csum++; 112 113 csum += (__force __u32)daddr; 114 if (csum < (__force __u32)daddr) 115 csum++; 116 117 csum += len + proto; 118 if (csum < len + proto) 119 csum++; 120 121 return (__force __wsum)csum; 122 } 123 124 /* 125 * computes the checksum of the TCP/UDP pseudo-header 126 * returns a 16-bit checksum, already complemented 127 */ 128 129 static inline __sum16 130 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 131 unsigned short len, unsigned short proto, 132 __wsum sum) 133 { 134 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); 135 } 136 137 /* 138 * this routine is used for miscellaneous IP-like checksums, mainly 139 * in icmp.c 140 */ 141 142 static inline __sum16 ip_compute_csum(const void *buff, int len) 143 { 144 return csum_fold(csum_partial(buff, len, 0)); 145 } 146 147 #endif /* _S390_CHECKSUM_H */ 148 149 150