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/kmsan-checks.h> 17 #include <linux/in6.h> 18 19 static inline __wsum cksm(const void *buff, int len, __wsum sum) 20 { 21 union register_pair rp = { 22 .even = (unsigned long)buff, 23 .odd = (unsigned long)len, 24 }; 25 26 instrument_read(buff, len); 27 kmsan_check_memory(buff, len); 28 asm volatile("\n" 29 "0: cksm %[sum],%[rp]\n" 30 " jo 0b\n" 31 : [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory"); 32 return sum; 33 } 34 35 __wsum csum_partial(const void *buff, int len, __wsum sum); 36 37 #define _HAVE_ARCH_CSUM_AND_COPY 38 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len); 39 40 /* 41 * Fold a partial checksum without adding pseudo headers. 42 */ 43 static inline __sum16 csum_fold(__wsum sum) 44 { 45 u32 csum = (__force u32) sum; 46 47 csum += (csum >> 16) | (csum << 16); 48 csum >>= 16; 49 return (__force __sum16) ~csum; 50 } 51 52 /* 53 * This is a version of ip_compute_csum() optimized for IP headers, 54 * which always checksums on 4 octet boundaries. 55 */ 56 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 57 { 58 __u64 csum = 0; 59 __u32 *ptr = (u32 *)iph; 60 61 csum += *ptr++; 62 csum += *ptr++; 63 csum += *ptr++; 64 csum += *ptr++; 65 ihl -= 4; 66 while (ihl--) 67 csum += *ptr++; 68 csum += (csum >> 32) | (csum << 32); 69 return csum_fold((__force __wsum)(csum >> 32)); 70 } 71 72 /* 73 * Computes the checksum of the TCP/UDP pseudo-header. 74 * Returns a 32-bit checksum. 75 */ 76 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 77 __u8 proto, __wsum sum) 78 { 79 __u64 csum = (__force __u64)sum; 80 81 csum += (__force __u32)saddr; 82 csum += (__force __u32)daddr; 83 csum += len; 84 csum += proto; 85 csum += (csum >> 32) | (csum << 32); 86 return (__force __wsum)(csum >> 32); 87 } 88 89 /* 90 * Computes the checksum of the TCP/UDP pseudo-header. 91 * Returns a 16-bit checksum, already complemented. 92 */ 93 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 94 __u8 proto, __wsum sum) 95 { 96 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 97 } 98 99 /* 100 * Used for miscellaneous IP-like checksums, mainly icmp. 101 */ 102 static inline __sum16 ip_compute_csum(const void *buff, int len) 103 { 104 return csum_fold(csum_partial(buff, len, 0)); 105 } 106 107 #define _HAVE_ARCH_IPV6_CSUM 108 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 109 const struct in6_addr *daddr, 110 __u32 len, __u8 proto, __wsum csum) 111 { 112 __u64 sum = (__force __u64)csum; 113 114 sum += (__force __u32)saddr->s6_addr32[0]; 115 sum += (__force __u32)saddr->s6_addr32[1]; 116 sum += (__force __u32)saddr->s6_addr32[2]; 117 sum += (__force __u32)saddr->s6_addr32[3]; 118 sum += (__force __u32)daddr->s6_addr32[0]; 119 sum += (__force __u32)daddr->s6_addr32[1]; 120 sum += (__force __u32)daddr->s6_addr32[2]; 121 sum += (__force __u32)daddr->s6_addr32[3]; 122 sum += len; 123 sum += proto; 124 sum += (sum >> 32) | (sum << 32); 125 return csum_fold((__force __wsum)(sum >> 32)); 126 } 127 128 #endif /* _S390_CHECKSUM_H */ 129