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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 | #ifndef _I386_CHECKSUM_H #define _I386_CHECKSUM_H /* * computes the checksum of a memory block at buff, length len, * and adds in "sum" (32-bit) * * returns a 32-bit number suitable for feeding into itself * or csum_tcpudp_magic * * this function must be called with even lengths, except * for the last fragment, which may be odd * * it's best to have buff aligned on a 32-bit boundary */ unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); /* * the same as csum_partial, but copies from src while it * checksums, and handles user-space pointer exceptions correctly, when needed. * * here even more important to align src and dst on a 32-bit (or even * better 64-bit) boundary */ unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum, int *src_err_ptr, int *dst_err_ptr); extern __inline__ unsigned int csum_partial_copy_nocheck ( const char *src, char *dst, int len, int sum) { int *src_err_ptr=NULL, *dst_err_ptr=NULL; return csum_partial_copy_generic ( src, dst, len, sum, src_err_ptr, dst_err_ptr); } extern __inline__ unsigned int csum_partial_copy_from_user ( const char *src, char *dst, int len, int sum, int *err_ptr) { int *dst_err_ptr=NULL; return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, dst_err_ptr); } /* * This combination is currently not used, but possible: */ extern __inline__ unsigned int csum_partial_copy_to_user ( const char *src, char *dst, int len, int sum, int *err_ptr) { int *src_err_ptr=NULL; return csum_partial_copy_generic ( src, dst, len, sum, src_err_ptr, err_ptr); } /* * These are the old (and unsafe) way of doing checksums, a warning message will be * printed if they are used and an exeption occurs. * * these functions should go away after some time. */ #define csum_partial_copy_fromuser csum_partial_copy unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum); /* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. * * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by * Arnt Gulbrandsen. */ static inline unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl) { unsigned int sum; __asm__ __volatile__(" movl (%1), %0 subl $4, %2 jbe 2f addl 4(%1), %0 adcl 8(%1), %0 adcl 12(%1), %0 1: adcl 16(%1), %0 lea 4(%1), %1 decl %2 jne 1b adcl $0, %0 movl %0, %2 shrl $16, %0 addw %w2, %w0 adcl $0, %0 notl %0 2: " /* Since the input registers which are loaded with iph and ipl are modified, we must also specify them as outputs, or gcc will assume they contain their original values. */ : "=r" (sum), "=r" (iph), "=r" (ihl) : "1" (iph), "2" (ihl)); return(sum); } /* * Fold a partial checksum */ static inline unsigned int csum_fold(unsigned int sum) { __asm__(" addl %1, %0 adcl $0xffff, %0 " : "=r" (sum) : "r" (sum << 16), "0" (sum & 0xffff0000) ); return (~sum) >> 16; } /* * computes the checksum of the TCP/UDP pseudo-header * returns a 16-bit checksum, already complemented */ static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int sum) { __asm__(" addl %1, %0 adcl %2, %0 adcl %3, %0 adcl $0, %0 " : "=r" (sum) : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); return csum_fold(sum); } /* * this routine is used for miscellaneous IP-like checksums, mainly * in icmp.c */ static inline unsigned short ip_compute_csum(unsigned char * buff, int len) { return csum_fold (csum_partial(buff, len, 0)); } #define _HAVE_ARCH_IPV6_CSUM static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u16 len, unsigned short proto, unsigned int sum) { __asm__(" addl 0(%1), %0 adcl 4(%1), %0 adcl 8(%1), %0 adcl 12(%1), %0 adcl 0(%2), %0 adcl 4(%2), %0 adcl 8(%2), %0 adcl 12(%2), %0 adcl %3, %0 adcl %4, %0 adcl $0, %0 " : "=&r" (sum) : "r" (saddr), "r" (daddr), "r"(htonl((__u32) (len))), "r"(htonl(proto)), "0"(sum)); return csum_fold(sum); } #endif |