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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 | #ifndef _PPC_CHECKSUM_H #define _PPC_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 */ extern unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); /* * Computes the checksum of a memory block at src, length len, * and adds in "sum" (32-bit), while copying the block to dst. * If an access exception occurs on src or dst, it stores -EFAULT * to *src_err or *dst_err respectively (if that pointer is not * NULL), and, for an error on src, zeroes the rest of dst. * * Like csum_partial, this must be called with even lengths, * except for the last fragment. */ extern unsigned int csum_partial_copy_generic(const char *src, char *dst, int len, unsigned int sum, int *src_err, int *dst_err); #define csum_partial_copy_from_user(src, dst, len, sum, errp) \ csum_partial_copy_generic((src), (dst), (len), (sum), (errp), 0) /* FIXME: this needs to be written to really do no check -- Cort */ #define csum_partial_copy_nocheck(src, dst, len, sum) \ csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0) /* * Old versions which ignore errors. */ #define csum_partial_copy(src, dst, len, sum) \ csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0) #define csum_partial_copy_fromuser(src, dst, len, sum) \ csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0) /* * turns a 32-bit partial checksum (e.g. from csum_partial) into a * 1's complement 16-bit checksum. */ static inline unsigned int csum_fold(unsigned int sum) { unsigned int tmp; /* swap the two 16-bit halves of sum */ __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); /* if there is a carry from adding the two 16-bit halves, it will carry from the lower half into the upper half, giving us the correct sum in the upper half. */ sum = ~(sum + tmp) >> 16; return 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)); } /* * FIXME: I swiped this one from the sparc and made minor modifications. * It may not be correct. -- Cort */ static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int sum) { __asm__(" addc %0,%0,%1 adde %0,%0,%2 adde %0,%0,%3 addze %0,%0 " : "=r" (sum) : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum)); return sum; } /* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. ihl is the number * of 32-bit words and is always >= 5. */ extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); /* * computes the checksum of the TCP/UDP pseudo-header * returns a 16-bit checksum, already complemented */ extern unsigned short csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int sum); #endif |