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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | #ifndef _I386_CHECKSUM_H |
| 2 | #define _I386_CHECKSUM_H |
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| 3 | |||
| 4 | #include <linux/in6.h> |
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| 5 | |||
| 6 | /* |
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| 7 | * computes the checksum of a memory block at buff, length len, |
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| 8 | * and adds in "sum" (32-bit) |
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| 9 | * |
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| 10 | * returns a 32-bit number suitable for feeding into itself |
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| 11 | * or csum_tcpudp_magic |
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| 12 | * |
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| 13 | * this function must be called with even lengths, except |
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| 14 | * for the last fragment, which may be odd |
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| 15 | * |
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| 16 | * it's best to have buff aligned on a 32-bit boundary |
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| 17 | */ |
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| 18 | asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); |
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| 19 | |||
| 20 | /* |
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| 21 | * the same as csum_partial, but copies from src while it |
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| 22 | * checksums, and handles user-space pointer exceptions correctly, when needed. |
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| 23 | * |
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| 24 | * here even more important to align src and dst on a 32-bit (or even |
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| 25 | * better 64-bit) boundary |
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| 26 | */ |
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| 27 | |||
| 28 | asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum, |
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| 29 | int *src_err_ptr, int *dst_err_ptr); |
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| 30 | |||
| 31 | /* |
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| 32 | * Note: when you get a NULL pointer exception here this means someone |
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| 33 | * passed in an incorrect kernel address to one of these functions. |
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| 34 | * |
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| 35 | * If you use these functions directly please don't forget the |
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| 36 | * verify_area(). |
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| 37 | */ |
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| 38 | static __inline__ |
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| 39 | unsigned int csum_partial_copy_nocheck ( const char *src, char *dst, |
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| 40 | int len, int sum) |
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| 41 | { |
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| 42 | return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL); |
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| 43 | } |
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| 44 | |||
| 45 | static __inline__ |
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| 46 | unsigned int csum_partial_copy_from_user ( const char *src, char *dst, |
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| 47 | int len, int sum, int *err_ptr) |
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| 48 | { |
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| 49 | return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL); |
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| 50 | } |
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| 51 | |||
| 52 | /* |
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| 53 | * This is a version of ip_compute_csum() optimized for IP headers, |
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| 54 | * which always checksum on 4 octet boundaries. |
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| 55 | * |
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| 56 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by |
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| 57 | * Arnt Gulbrandsen. |
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| 58 | */ |
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| 59 | static inline unsigned short ip_fast_csum(unsigned char * iph, |
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| 60 | unsigned int ihl) |
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| 61 | { |
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| 62 | unsigned int sum; |
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| 63 | |||
| 64 | __asm__ __volatile__( |
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| 65 | "movl (%1), %0 ;\n" |
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| 66 | "subl $4, %2 ;\n" |
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| 67 | "jbe 2f ;\n" |
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| 68 | "addl 4(%1), %0 ;\n" |
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| 69 | "adcl 8(%1), %0 ;\n" |
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| 70 | "adcl 12(%1), %0 ;\n" |
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| 71 | "1: adcl 16(%1), %0 ;\n" |
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| 72 | "lea 4(%1), %1 ;\n" |
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| 73 | "decl %2 ;\n" |
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| 74 | "jne 1b ;\n" |
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| 75 | "adcl $0, %0 ;\n" |
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| 76 | "movl %0, %2 ;\n" |
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| 77 | "shrl $16, %0 ;\n" |
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| 78 | "addw %w2, %w0 ;\n" |
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| 79 | "adcl $0, %0 ;\n" |
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| 80 | "notl %0 ;\n" |
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| 81 | "2: ;\n" |
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| 82 | /* Since the input registers which are loaded with iph and ipl |
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| 83 | are modified, we must also specify them as outputs, or gcc |
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| 84 | will assume they contain their original values. */ |
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| 85 | : "=r" (sum), "=r" (iph), "=r" (ihl) |
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| 86 | : "1" (iph), "2" (ihl) |
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| 87 | : "memory"); |
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| 88 | return(sum); |
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| 89 | } |
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| 90 | |||
| 91 | /* |
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| 92 | * Fold a partial checksum |
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| 93 | */ |
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| 94 | |||
| 95 | static inline unsigned int csum_fold(unsigned int sum) |
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| 96 | { |
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| 97 | __asm__( |
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| 98 | "addl %1, %0 ;\n" |
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| 99 | "adcl $0xffff, %0 ;\n" |
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| 100 | : "=r" (sum) |
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| 101 | : "r" (sum << 16), "0" (sum & 0xffff0000) |
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| 102 | ); |
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| 103 | return (~sum) >> 16; |
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| 104 | } |
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| 105 | |||
| 106 | static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, |
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| 107 | unsigned long daddr, |
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| 108 | unsigned short len, |
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| 109 | unsigned short proto, |
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| 110 | unsigned int sum) |
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| 111 | { |
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| 112 | __asm__( |
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| 113 | "addl %1, %0 ;\n" |
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| 114 | "adcl %2, %0 ;\n" |
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| 115 | "adcl %3, %0 ;\n" |
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| 116 | "adcl $0, %0 ;\n" |
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| 117 | : "=r" (sum) |
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| 118 | : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum)); |
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| 119 | return sum; |
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| 120 | } |
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| 121 | |||
| 122 | /* |
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| 123 | * computes the checksum of the TCP/UDP pseudo-header |
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| 124 | * returns a 16-bit checksum, already complemented |
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| 125 | */ |
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| 126 | static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, |
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| 127 | unsigned long daddr, |
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| 128 | unsigned short len, |
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| 129 | unsigned short proto, |
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| 130 | unsigned int sum) |
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| 131 | { |
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| 132 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); |
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| 133 | } |
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| 134 | |||
| 135 | /* |
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| 136 | * this routine is used for miscellaneous IP-like checksums, mainly |
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| 137 | * in icmp.c |
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| 138 | */ |
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| 139 | |||
| 140 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) |
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| 141 | { |
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| 142 | return csum_fold (csum_partial(buff, len, 0)); |
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| 143 | } |
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| 144 | |||
| 145 | #define _HAVE_ARCH_IPV6_CSUM |
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| 146 | static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, |
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| 147 | struct in6_addr *daddr, |
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| 148 | __u32 len, |
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| 149 | unsigned short proto, |
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| 150 | unsigned int sum) |
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| 151 | { |
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| 152 | __asm__( |
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| 153 | "addl 0(%1), %0 ;\n" |
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| 154 | "adcl 4(%1), %0 ;\n" |
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| 155 | "adcl 8(%1), %0 ;\n" |
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| 156 | "adcl 12(%1), %0 ;\n" |
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| 157 | "adcl 0(%2), %0 ;\n" |
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| 158 | "adcl 4(%2), %0 ;\n" |
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| 159 | "adcl 8(%2), %0 ;\n" |
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| 160 | "adcl 12(%2), %0 ;\n" |
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| 161 | "adcl %3, %0 ;\n" |
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| 162 | "adcl %4, %0 ;\n" |
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| 163 | "adcl $0, %0 ;\n" |
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| 164 | : "=&r" (sum) |
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| 165 | : "r" (saddr), "r" (daddr), |
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| 166 | "r"(htonl(len)), "r"(htonl(proto)), "0"(sum)); |
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| 167 | |||
| 168 | return csum_fold(sum); |
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| 169 | } |
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| 170 | |||
| 171 | /* |
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| 172 | * Copy and checksum to user |
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| 173 | */ |
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| 174 | #define HAVE_CSUM_COPY_USER |
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| 175 | static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst, |
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| 176 | int len, int sum, int *err_ptr) |
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| 177 | { |
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| 178 | if (access_ok(VERIFY_WRITE, dst, len)) |
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| 179 | return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr); |
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| 180 | |||
| 181 | if (len) |
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| 182 | *err_ptr = -EFAULT; |
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| 183 | |||
| 184 | return -1; /* invalid checksum */ |
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| 185 | } |
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| 186 | |||
| 187 | #endif |