1/* 2 * linux/include/asm-arm/checksum.h 3 * 4 * IP checksum routines 5 * 6 * Copyright (C) Original authors of ../asm-i386/checksum.h 7 * Copyright (C) 1996-1999 Russell King 8 */ 9#ifndef __ASM_ARM_CHECKSUM_H 10#define __ASM_ARM_CHECKSUM_H 11 12#include <linux/in6.h> 13 14/* 15 * computes the checksum of a memory block at buff, length len, 16 * and adds in "sum" (32-bit) 17 * 18 * returns a 32-bit number suitable for feeding into itself 19 * or csum_tcpudp_magic 20 * 21 * this function must be called with even lengths, except 22 * for the last fragment, which may be odd 23 * 24 * it's best to have buff aligned on a 32-bit boundary 25 */ 26__wsum csum_partial(const void *buff, int len, __wsum sum); 27 28/* 29 * the same as csum_partial, but copies from src while it 30 * checksums, and handles user-space pointer exceptions correctly, when needed. 31 * 32 * here even more important to align src and dst on a 32-bit (or even 33 * better 64-bit) boundary 34 */ 35 36__wsum 37csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum); 38 39__wsum 40csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr); 41 42/* 43 * This is a version of ip_compute_csum() optimized for IP headers, 44 * which always checksum on 4 octet boundaries. 45 */ 46static inline __sum16 47ip_fast_csum(const void *iph, unsigned int ihl) 48{ 49 unsigned int sum, tmp1; 50 51 __asm__ __volatile__( 52 "ldr %0, [%1], #4 @ ip_fast_csum \n\ 53 ldr %3, [%1], #4 \n\ 54 sub %2, %2, #5 \n\ 55 adds %0, %0, %3 \n\ 56 ldr %3, [%1], #4 \n\ 57 adcs %0, %0, %3 \n\ 58 ldr %3, [%1], #4 \n\ 591: adcs %0, %0, %3 \n\ 60 ldr %3, [%1], #4 \n\ 61 tst %2, #15 @ do this carefully \n\ 62 subne %2, %2, #1 @ without destroying \n\ 63 bne 1b @ the carry flag \n\ 64 adcs %0, %0, %3 \n\ 65 adc %0, %0, #0 \n\ 66 adds %0, %0, %0, lsl #16 \n\ 67 addcs %0, %0, #0x10000 \n\ 68 mvn %0, %0 \n\ 69 mov %0, %0, lsr #16" 70 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) 71 : "1" (iph), "2" (ihl) 72 : "cc"); 73 return (__force __sum16)sum; 74} 75 76/* 77 * Fold a partial checksum without adding pseudo headers 78 */ 79static inline __sum16 csum_fold(__wsum sum) 80{ 81 __asm__( 82 "adds %0, %1, %1, lsl #16 @ csum_fold \n\ 83 addcs %0, %0, #0x10000" 84 : "=r" (sum) 85 : "r" (sum) 86 : "cc"); 87 return (__force __sum16)(~(__force u32)sum >> 16); 88} 89 90static inline __wsum 91csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, 92 unsigned short proto, __wsum sum) 93{ 94 __asm__( 95 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\ 96 adcs %0, %0, %3 \n\ 97 adcs %0, %0, %4 \n\ 98 adcs %0, %0, %5 \n\ 99 adc %0, %0, #0" 100 : "=&r"(sum) 101 : "r" (sum), "r" (daddr), "r" (saddr), "r" (htons(len)), "Ir" (htons(proto)) 102 : "cc"); 103 return sum; 104} 105/* 106 * computes the checksum of the TCP/UDP pseudo-header 107 * returns a 16-bit checksum, already complemented 108 */ 109static inline __sum16 110csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len, 111 unsigned short proto, __wsum sum) 112{ 113 __asm__( 114 "adds %0, %1, %2 @ csum_tcpudp_magic \n\ 115 adcs %0, %0, %3 \n\ 116 adcs %0, %0, %4 \n\ 117 adcs %0, %0, %5 \n\ 118 adc %0, %0, #0 \n\ 119 adds %0, %0, %0, lsl #16 \n\ 120 addcs %0, %0, #0x10000 \n\ 121 mvn %0, %0" 122 : "=&r"(sum) 123 : "r" (sum), "r" (daddr), "r" (saddr), "r" (htons(len)), "Ir" (htons(proto)) 124 : "cc"); 125 return (__force __sum16)((__force u32)sum >> 16); 126} 127 128 129/* 130 * this routine is used for miscellaneous IP-like checksums, mainly 131 * in icmp.c 132 */ 133static inline __sum16 134ip_compute_csum(const void *buff, int len) 135{ 136 return csum_fold(csum_partial(buff, len, 0)); 137} 138 139#define _HAVE_ARCH_IPV6_CSUM 140extern __wsum 141__csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, 142 __be32 proto, __wsum sum); 143 144static inline __sum16 145csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __u32 len, 146 unsigned short proto, __wsum sum) 147{ 148 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), 149 htonl(proto), sum)); 150} 151#endif 152