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/* 13 * computes the checksum of a memory block at buff, length len, 14 * and adds in "sum" (32-bit) 15 * 16 * returns a 32-bit number suitable for feeding into itself 17 * or csum_tcpudp_magic 18 * 19 * this function must be called with even lengths, except 20 * for the last fragment, which may be odd 21 * 22 * it's best to have buff aligned on a 32-bit boundary 23 */ 24unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); 25 26/* 27 * the same as csum_partial, but copies from src while it 28 * checksums, and handles user-space pointer exceptions correctly, when needed. 29 * 30 * here even more important to align src and dst on a 32-bit (or even 31 * better 64-bit) boundary 32 */ 33 34unsigned int 35csum_partial_copy_nocheck(const char *src, char *dst, int len, int sum); 36 37unsigned int 38csum_partial_copy_from_user(const char *src, char *dst, int len, int sum, int *err_ptr); 39 40/* 41 * These are the old (and unsafe) way of doing checksums, a warning message will be 42 * printed if they are used and an exception occurs. 43 * 44 * these functions should go away after some time. 45 */ 46#define csum_partial_copy(src,dst,len,sum) csum_partial_copy_nocheck(src,dst,len,sum) 47 48/* 49 * This is a version of ip_compute_csum() optimized for IP headers, 50 * which always checksum on 4 octet boundaries. 51 */ 52static inline unsigned short 53ip_fast_csum(unsigned char * iph, unsigned int ihl) 54{ 55 unsigned int sum, tmp1; 56 57 __asm__ __volatile__( 58 "ldr %0, [%1], #4 @ ip_fast_csum \n\ 59 ldr %3, [%1], #4 \n\ 60 sub %2, %2, #5 \n\ 61 adds %0, %0, %3 \n\ 62 ldr %3, [%1], #4 \n\ 63 adcs %0, %0, %3 \n\ 64 ldr %3, [%1], #4 \n\ 651: adcs %0, %0, %3 \n\ 66 ldr %3, [%1], #4 \n\ 67 tst %2, #15 @ do this carefully \n\ 68 subne %2, %2, #1 @ without destroying \n\ 69 bne 1b @ the carry flag \n\ 70 adcs %0, %0, %3 \n\ 71 adc %0, %0, #0 \n\ 72 adds %0, %0, %0, lsl #16 \n\ 73 addcs %0, %0, #0x10000 \n\ 74 mvn %0, %0 \n\ 75 mov %0, %0, lsr #16" 76 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) 77 : "1" (iph), "2" (ihl) 78 : "cc"); 79 return sum; 80} 81 82/* 83 * Fold a partial checksum without adding pseudo headers 84 */ 85static inline unsigned int 86csum_fold(unsigned int sum) 87{ 88 __asm__( 89 "adds %0, %1, %1, lsl #16 @ csum_fold \n\ 90 addcs %0, %0, #0x10000" 91 : "=r" (sum) 92 : "r" (sum) 93 : "cc"); 94 return (~sum) >> 16; 95} 96 97static inline unsigned int 98csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len, 99 unsigned int proto, unsigned int sum) 100{ 101 __asm__( 102 "adds %0, %1, %2 @ csum_tcpudp_nofold \n\ 103 adcs %0, %0, %3 \n\ 104 adcs %0, %0, %4 \n\ 105 adcs %0, %0, %5 \n\ 106 adc %0, %0, #0" 107 : "=&r"(sum) 108 : "r" (sum), "r" (daddr), "r" (saddr), "r" (ntohs(len) << 16), "Ir" (proto << 8) 109 : "cc"); 110 return sum; 111} 112/* 113 * computes the checksum of the TCP/UDP pseudo-header 114 * returns a 16-bit checksum, already complemented 115 */ 116static inline unsigned short int 117csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len, 118 unsigned int proto, unsigned int sum) 119{ 120 __asm__( 121 "adds %0, %1, %2 @ csum_tcpudp_magic \n\ 122 adcs %0, %0, %3 \n\ 123 adcs %0, %0, %4 \n\ 124 adcs %0, %0, %5 \n\ 125 adc %0, %0, #0 \n\ 126 adds %0, %0, %0, lsl #16 \n\ 127 addcs %0, %0, #0x10000 \n\ 128 mvn %0, %0" 129 : "=&r"(sum) 130 : "r" (sum), "r" (daddr), "r" (saddr), "r" (ntohs(len)), "Ir" (proto << 8) 131 : "cc"); 132 return sum >> 16; 133} 134 135 136/* 137 * this routine is used for miscellaneous IP-like checksums, mainly 138 * in icmp.c 139 */ 140static inline unsigned short 141ip_compute_csum(unsigned char * buff, int len) 142{ 143 return csum_fold(csum_partial(buff, len, 0)); 144} 145 146#define _HAVE_ARCH_IPV6_CSUM 147extern unsigned long 148__csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len, 149 __u32 proto, unsigned int sum); 150 151static inline unsigned short int 152csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len, 153 unsigned short proto, unsigned int sum) 154{ 155 return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), 156 htonl(proto), sum)); 157} 158#endif 159