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Rev | Author | Line No. | Line |
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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 |