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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 | /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */ #ifndef _CRIS_CHECKSUM_H #define _CRIS_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 * * here even more important to align src and dst on a 32-bit (or even * better 64-bit) boundary */ unsigned int csum_partial_copy_nocheck(const char *src, char *dst, int len, unsigned int sum); /* * Fold a partial checksum into a word */ static inline unsigned int csum_fold(unsigned int sum) { /* the while loop is unnecessary really, it's always enough with two iterations */ while(sum >> 16) sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */ return ~sum; } /* Checksum some values used in TCP/UDP headers. * * The gain by doing this in asm is that C will not generate carry-additions * for the 32-bit components of the checksum, so otherwise we would have had * to split all of those into 16-bit components, then add. */ static inline unsigned int csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int sum) { int res; __asm__ ("add.d %2, %0\n\t" "ax\n\t" "add.d %3, %0\n\t" "ax\n\t" "add.d %4, %0\n\t" "ax\n\t" "addq 0, %0\n" : "=r" (res) : "0" (sum), "r" (daddr), "r" (saddr), "r" ((ntohs(len) << 16) + (proto << 8))); return res; } extern unsigned int csum_partial_copy_from_user(const char *src, char *dst, int len, unsigned int sum, int *errptr); /* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. * */ static inline unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl) { return csum_fold(csum_partial(iph, ihl * 4, 0)); } /* * 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) { return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,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)); } #endif |