1 #ifndef _ASM_X86_CHECKSUM_32_H 2 #define _ASM_X86_CHECKSUM_32_H 3 4 #include <linux/in6.h> 5 6 #include <asm/uaccess.h> 7 8 /* 9 * computes the checksum of a memory block at buff, length len, 10 * and adds in "sum" (32-bit) 11 * 12 * returns a 32-bit number suitable for feeding into itself 13 * or csum_tcpudp_magic 14 * 15 * this function must be called with even lengths, except 16 * for the last fragment, which may be odd 17 * 18 * it's best to have buff aligned on a 32-bit boundary 19 */ 20 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum); 21 22 /* 23 * the same as csum_partial, but copies from src while it 24 * checksums, and handles user-space pointer exceptions correctly, when needed. 25 * 26 * here even more important to align src and dst on a 32-bit (or even 27 * better 64-bit) boundary 28 */ 29 30 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, 31 int len, __wsum sum, 32 int *src_err_ptr, int *dst_err_ptr); 33 34 /* 35 * Note: when you get a NULL pointer exception here this means someone 36 * passed in an incorrect kernel address to one of these functions. 37 * 38 * If you use these functions directly please don't forget the 39 * access_ok(). 40 */ 41 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, 42 int len, __wsum sum) 43 { 44 return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); 45 } 46 47 static inline __wsum csum_partial_copy_from_user(const void __user *src, 48 void *dst, 49 int len, __wsum sum, 50 int *err_ptr) 51 { 52 __wsum ret; 53 54 might_sleep(); 55 stac(); 56 ret = csum_partial_copy_generic((__force void *)src, dst, 57 len, sum, err_ptr, NULL); 58 clac(); 59 60 return ret; 61 } 62 63 /* 64 * This is a version of ip_compute_csum() optimized for IP headers, 65 * which always checksum on 4 octet boundaries. 66 * 67 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 68 * Arnt Gulbrandsen. 69 */ 70 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 71 { 72 unsigned int sum; 73 74 asm volatile("movl (%1), %0 ;\n" 75 "subl $4, %2 ;\n" 76 "jbe 2f ;\n" 77 "addl 4(%1), %0 ;\n" 78 "adcl 8(%1), %0 ;\n" 79 "adcl 12(%1), %0;\n" 80 "1: adcl 16(%1), %0 ;\n" 81 "lea 4(%1), %1 ;\n" 82 "decl %2 ;\n" 83 "jne 1b ;\n" 84 "adcl $0, %0 ;\n" 85 "movl %0, %2 ;\n" 86 "shrl $16, %0 ;\n" 87 "addw %w2, %w0 ;\n" 88 "adcl $0, %0 ;\n" 89 "notl %0 ;\n" 90 "2: ;\n" 91 /* Since the input registers which are loaded with iph and ihl 92 are modified, we must also specify them as outputs, or gcc 93 will assume they contain their original values. */ 94 : "=r" (sum), "=r" (iph), "=r" (ihl) 95 : "1" (iph), "2" (ihl) 96 : "memory"); 97 return (__force __sum16)sum; 98 } 99 100 /* 101 * Fold a partial checksum 102 */ 103 104 static inline __sum16 csum_fold(__wsum sum) 105 { 106 asm("addl %1, %0 ;\n" 107 "adcl $0xffff, %0 ;\n" 108 : "=r" (sum) 109 : "r" ((__force u32)sum << 16), 110 "0" ((__force u32)sum & 0xffff0000)); 111 return (__force __sum16)(~(__force u32)sum >> 16); 112 } 113 114 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 115 unsigned short len, 116 unsigned short proto, 117 __wsum sum) 118 { 119 asm("addl %1, %0 ;\n" 120 "adcl %2, %0 ;\n" 121 "adcl %3, %0 ;\n" 122 "adcl $0, %0 ;\n" 123 : "=r" (sum) 124 : "g" (daddr), "g"(saddr), 125 "g" ((len + proto) << 8), "0" (sum)); 126 return sum; 127 } 128 129 /* 130 * computes the checksum of the TCP/UDP pseudo-header 131 * returns a 16-bit checksum, already complemented 132 */ 133 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 134 unsigned short len, 135 unsigned short proto, 136 __wsum sum) 137 { 138 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 139 } 140 141 /* 142 * this routine is used for miscellaneous IP-like checksums, mainly 143 * in icmp.c 144 */ 145 146 static inline __sum16 ip_compute_csum(const void *buff, int len) 147 { 148 return csum_fold(csum_partial(buff, len, 0)); 149 } 150 151 #define _HAVE_ARCH_IPV6_CSUM 152 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 153 const struct in6_addr *daddr, 154 __u32 len, unsigned short proto, 155 __wsum sum) 156 { 157 asm("addl 0(%1), %0 ;\n" 158 "adcl 4(%1), %0 ;\n" 159 "adcl 8(%1), %0 ;\n" 160 "adcl 12(%1), %0 ;\n" 161 "adcl 0(%2), %0 ;\n" 162 "adcl 4(%2), %0 ;\n" 163 "adcl 8(%2), %0 ;\n" 164 "adcl 12(%2), %0 ;\n" 165 "adcl %3, %0 ;\n" 166 "adcl %4, %0 ;\n" 167 "adcl $0, %0 ;\n" 168 : "=&r" (sum) 169 : "r" (saddr), "r" (daddr), 170 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) 171 : "memory"); 172 173 return csum_fold(sum); 174 } 175 176 /* 177 * Copy and checksum to user 178 */ 179 #define HAVE_CSUM_COPY_USER 180 static inline __wsum csum_and_copy_to_user(const void *src, 181 void __user *dst, 182 int len, __wsum sum, 183 int *err_ptr) 184 { 185 __wsum ret; 186 187 might_sleep(); 188 if (access_ok(VERIFY_WRITE, dst, len)) { 189 stac(); 190 ret = csum_partial_copy_generic(src, (__force void *)dst, 191 len, sum, NULL, err_ptr); 192 clac(); 193 return ret; 194 } 195 196 if (len) 197 *err_ptr = -EFAULT; 198 199 return (__force __wsum)-1; /* invalid checksum */ 200 } 201 202 #endif /* _ASM_X86_CHECKSUM_32_H */ 203