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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 | /* * Licensed under the GPL */ #ifndef __UM_SYSDEP_CHECKSUM_H #define __UM_SYSDEP_CHECKSUM_H #include "linux/string.h" #include "linux/in6.h" #include "asm/uaccess.h" extern unsigned csum_partial(const unsigned char *buff, unsigned len, unsigned sum); /* * Note: when you get a NULL pointer exception here this means someone * passed in an incorrect kernel address to one of these functions. * * If you use these functions directly please don't forget the * access_ok(). */ static __inline__ unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len, int sum) { memcpy(dst, src, len); return(csum_partial(dst, len, sum)); } static __inline__ unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len, int sum, int *err_ptr) { if(copy_from_user(dst, src, len)){ *err_ptr = -EFAULT; return(-1); } return csum_partial(dst, len, sum); } /** * csum_fold - Fold and invert a 32bit checksum. * sum: 32bit unfolded sum * * Fold a 32bit running checksum to 16bit and invert it. This is usually * the last step before putting a checksum into a packet. * Make sure not to mix with 64bit checksums. */ static inline unsigned int csum_fold(unsigned int sum) { __asm__( " addl %1,%0\n" " adcl $0xffff,%0" : "=r" (sum) : "r" (sum << 16), "0" (sum & 0xffff0000) ); return (~sum) >> 16; } /** * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum. * @saddr: source address * @daddr: destination address * @len: length of packet * @proto: ip protocol of packet * @sum: initial sum to be added in (32bit unfolded) * * Returns the pseudo header checksum the input data. Result is * 32bit unfolded. */ static inline unsigned long csum_tcpudp_nofold(unsigned saddr, unsigned daddr, unsigned short len, unsigned short proto, unsigned int sum) { asm(" addl %1, %0\n" " adcl %2, %0\n" " adcl %3, %0\n" " adcl $0, %0\n" : "=r" (sum) : "g" (daddr), "g" (saddr), "g" ((ntohs(len)<<16)+proto*256), "0" (sum)); return sum; } /* * 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)); } /** * ip_fast_csum - Compute the IPv4 header checksum efficiently. * iph: ipv4 header * ihl: length of header / 4 */ static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl) { unsigned int sum; asm( " movl (%1), %0\n" " subl $4, %2\n" " jbe 2f\n" " addl 4(%1), %0\n" " adcl 8(%1), %0\n" " adcl 12(%1), %0\n" "1: adcl 16(%1), %0\n" " lea 4(%1), %1\n" " decl %2\n" " jne 1b\n" " adcl $0, %0\n" " movl %0, %2\n" " shrl $16, %0\n" " addw %w2, %w0\n" " adcl $0, %0\n" " notl %0\n" "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) : "memory"); return(sum); } static inline unsigned add32_with_carry(unsigned a, unsigned b) { asm("addl %2,%0\n\t" "adcl $0,%0" : "=r" (a) : "0" (a), "r" (b)); return a; } extern unsigned short ip_compute_csum(unsigned char * buff, int len); #endif |