1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * S390 fast network checksum routines 4 * 5 * S390 version 6 * Copyright IBM Corp. 1999 7 * Author(s): Ulrich Hild (first version) 8 * Martin Schwidefsky (heavily optimized CKSM version) 9 * D.J. Barrow (third attempt) 10 */ 11 12 #ifndef _S390_CHECKSUM_H 13 #define _S390_CHECKSUM_H 14 15 #include <linux/instrumented.h> 16 #include <linux/in6.h> 17 18 static inline __wsum cksm(const void *buff, int len, __wsum sum) 19 { 20 union register_pair rp = { 21 .even = (unsigned long)buff, 22 .odd = (unsigned long)len, 23 }; 24 25 instrument_read(buff, len); 26 asm volatile("\n" 27 "0: cksm %[sum],%[rp]\n" 28 " jo 0b\n" 29 : [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory"); 30 return sum; 31 } 32 33 __wsum csum_partial(const void *buff, int len, __wsum sum); 34 35 #define _HAVE_ARCH_CSUM_AND_COPY 36 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len); 37 38 /* 39 * Fold a partial checksum without adding pseudo headers. 40 */ 41 static inline __sum16 csum_fold(__wsum sum) 42 { 43 u32 csum = (__force u32) sum; 44 45 csum += (csum >> 16) | (csum << 16); 46 csum >>= 16; 47 return (__force __sum16) ~csum; 48 } 49 50 /* 51 * This is a version of ip_compute_csum() optimized for IP headers, 52 * which always checksums on 4 octet boundaries. 53 */ 54 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 55 { 56 __u64 csum = 0; 57 __u32 *ptr = (u32 *)iph; 58 59 csum += *ptr++; 60 csum += *ptr++; 61 csum += *ptr++; 62 csum += *ptr++; 63 ihl -= 4; 64 while (ihl--) 65 csum += *ptr++; 66 csum += (csum >> 32) | (csum << 32); 67 return csum_fold((__force __wsum)(csum >> 32)); 68 } 69 70 /* 71 * Computes the checksum of the TCP/UDP pseudo-header. 72 * Returns a 32-bit checksum. 73 */ 74 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 75 __u8 proto, __wsum sum) 76 { 77 __u64 csum = (__force __u64)sum; 78 79 csum += (__force __u32)saddr; 80 csum += (__force __u32)daddr; 81 csum += len; 82 csum += proto; 83 csum += (csum >> 32) | (csum << 32); 84 return (__force __wsum)(csum >> 32); 85 } 86 87 /* 88 * Computes the checksum of the TCP/UDP pseudo-header. 89 * Returns a 16-bit checksum, already complemented. 90 */ 91 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 92 __u8 proto, __wsum sum) 93 { 94 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 95 } 96 97 /* 98 * Used for miscellaneous IP-like checksums, mainly icmp. 99 */ 100 static inline __sum16 ip_compute_csum(const void *buff, int len) 101 { 102 return csum_fold(csum_partial(buff, len, 0)); 103 } 104 105 #define _HAVE_ARCH_IPV6_CSUM 106 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 107 const struct in6_addr *daddr, 108 __u32 len, __u8 proto, __wsum csum) 109 { 110 __u64 sum = (__force __u64)csum; 111 112 sum += (__force __u32)saddr->s6_addr32[0]; 113 sum += (__force __u32)saddr->s6_addr32[1]; 114 sum += (__force __u32)saddr->s6_addr32[2]; 115 sum += (__force __u32)saddr->s6_addr32[3]; 116 sum += (__force __u32)daddr->s6_addr32[0]; 117 sum += (__force __u32)daddr->s6_addr32[1]; 118 sum += (__force __u32)daddr->s6_addr32[2]; 119 sum += (__force __u32)daddr->s6_addr32[3]; 120 sum += len; 121 sum += proto; 122 sum += (sum >> 32) | (sum << 32); 123 return csum_fold((__force __wsum)(sum >> 32)); 124 } 125 126 #endif /* _S390_CHECKSUM_H */ 127