1#ifndef _I386_CHECKSUM_H 2#define _I386_CHECKSUM_H 3 4#include <linux/in6.h> 5 6#include <asm/uaccess.h> 7 8/* 9 * computes the checksum of a memory block at buff, length len, 10 * and adds in "sum" (32-bit) 11 * 12 * returns a 32-bit number suitable for feeding into itself 13 * or csum_tcpudp_magic 14 * 15 * this function must be called with even lengths, except 16 * for the last fragment, which may be odd 17 * 18 * it's best to have buff aligned on a 32-bit boundary 19 */ 20asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum); 21 22/* 23 * the same as csum_partial, but copies from src while it 24 * checksums, and handles user-space pointer exceptions correctly, when needed. 25 * 26 * here even more important to align src and dst on a 32-bit (or even 27 * better 64-bit) boundary 28 */ 29 30asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, 31 int len, __wsum sum, int *src_err_ptr, int *dst_err_ptr); 32 33/* 34 * Note: when you get a NULL pointer exception here this means someone 35 * passed in an incorrect kernel address to one of these functions. 36 * 37 * If you use these functions directly please don't forget the 38 * access_ok(). 39 */ 40static __inline__ 41__wsum csum_partial_copy_nocheck (const void *src, void *dst, 42 int len, __wsum sum) 43{ 44 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL); 45} 46 47static __inline__ 48__wsum csum_partial_copy_from_user(const void __user *src, void *dst, 49 int len, __wsum sum, int *err_ptr) 50{ 51 might_sleep(); 52 return csum_partial_copy_generic((__force void *)src, dst, 53 len, sum, err_ptr, NULL); 54} 55 56/* 57 * This is a version of ip_compute_csum() optimized for IP headers, 58 * which always checksum on 4 octet boundaries. 59 * 60 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 61 * Arnt Gulbrandsen. 62 */ 63static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 64{ 65 unsigned int sum; 66 67 __asm__ __volatile__( 68 "movl (%1), %0 ;\n" 69 "subl $4, %2 ;\n" 70 "jbe 2f ;\n" 71 "addl 4(%1), %0 ;\n" 72 "adcl 8(%1), %0 ;\n" 73 "adcl 12(%1), %0 ;\n" 74"1: adcl 16(%1), %0 ;\n" 75 "lea 4(%1), %1 ;\n" 76 "decl %2 ;\n" 77 "jne 1b ;\n" 78 "adcl $0, %0 ;\n" 79 "movl %0, %2 ;\n" 80 "shrl $16, %0 ;\n" 81 "addw %w2, %w0 ;\n" 82 "adcl $0, %0 ;\n" 83 "notl %0 ;\n" 84"2: ;\n" 85 /* Since the input registers which are loaded with iph and ihl 86 are modified, we must also specify them as outputs, or gcc 87 will assume they contain their original values. */ 88 : "=r" (sum), "=r" (iph), "=r" (ihl) 89 : "1" (iph), "2" (ihl) 90 : "memory"); 91 return (__force __sum16)sum; 92} 93 94/* 95 * Fold a partial checksum 96 */ 97 98static inline __sum16 csum_fold(__wsum sum) 99{ 100 __asm__( 101 "addl %1, %0 ;\n" 102 "adcl $0xffff, %0 ;\n" 103 : "=r" (sum) 104 : "r" ((__force u32)sum << 16), 105 "0" ((__force u32)sum & 0xffff0000) 106 ); 107 return (__force __sum16)(~(__force u32)sum >> 16); 108} 109 110static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 111 unsigned short len, 112 unsigned short proto, 113 __wsum sum) 114{ 115 __asm__( 116 "addl %1, %0 ;\n" 117 "adcl %2, %0 ;\n" 118 "adcl %3, %0 ;\n" 119 "adcl $0, %0 ;\n" 120 : "=r" (sum) 121 : "g" (daddr), "g"(saddr), "g"((len + proto) << 8), "0"(sum)); 122 return sum; 123} 124 125/* 126 * computes the checksum of the TCP/UDP pseudo-header 127 * returns a 16-bit checksum, already complemented 128 */ 129static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 130 unsigned short len, 131 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 142static inline __sum16 ip_compute_csum(const void *buff, int len) 143{ 144 return csum_fold (csum_partial(buff, len, 0)); 145} 146 147#define _HAVE_ARCH_IPV6_CSUM 148static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 149 const struct in6_addr *daddr, 150 __u32 len, unsigned short proto, 151 __wsum sum) 152{ 153 __asm__( 154 "addl 0(%1), %0 ;\n" 155 "adcl 4(%1), %0 ;\n" 156 "adcl 8(%1), %0 ;\n" 157 "adcl 12(%1), %0 ;\n" 158 "adcl 0(%2), %0 ;\n" 159 "adcl 4(%2), %0 ;\n" 160 "adcl 8(%2), %0 ;\n" 161 "adcl 12(%2), %0 ;\n" 162 "adcl %3, %0 ;\n" 163 "adcl %4, %0 ;\n" 164 "adcl $0, %0 ;\n" 165 : "=&r" (sum) 166 : "r" (saddr), "r" (daddr), 167 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); 168 169 return csum_fold(sum); 170} 171 172/* 173 * Copy and checksum to user 174 */ 175#define HAVE_CSUM_COPY_USER 176static __inline__ __wsum csum_and_copy_to_user(const void *src, 177 void __user *dst, 178 int len, __wsum sum, 179 int *err_ptr) 180{ 181 might_sleep(); 182 if (access_ok(VERIFY_WRITE, dst, len)) 183 return csum_partial_copy_generic(src, (__force void *)dst, len, sum, NULL, err_ptr); 184 185 if (len) 186 *err_ptr = -EFAULT; 187 188 return (__force __wsum)-1; /* invalid checksum */ 189} 190 191#endif 192