1 #ifndef _ASM_X86_CHECKSUM_32_H 2 #define _ASM_X86_CHECKSUM_32_H 3 4 #include <linux/in6.h> 5 #include <linux/uaccess.h> 6 7 /* 8 * computes the checksum of a memory block at buff, length len, 9 * and adds in "sum" (32-bit) 10 * 11 * returns a 32-bit number suitable for feeding into itself 12 * or csum_tcpudp_magic 13 * 14 * this function must be called with even lengths, except 15 * for the last fragment, which may be odd 16 * 17 * it's best to have buff aligned on a 32-bit boundary 18 */ 19 asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum); 20 21 /* 22 * the same as csum_partial, but copies from src while it 23 * checksums, and handles user-space pointer exceptions correctly, when needed. 24 * 25 * here even more important to align src and dst on a 32-bit (or even 26 * better 64-bit) boundary 27 */ 28 29 asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, 30 int len, __wsum sum, 31 int *src_err_ptr, int *dst_err_ptr); 32 33 /* 34 * Note: when you get a NULL pointer exception here this means someone 35 * passed in an incorrect kernel address to one of these functions. 36 * 37 * If you use these functions directly please don't forget the 38 * access_ok(). 39 */ 40 static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, 41 int len, __wsum sum) 42 { 43 return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); 44 } 45 46 static inline __wsum csum_partial_copy_from_user(const void __user *src, 47 void *dst, 48 int len, __wsum sum, 49 int *err_ptr) 50 { 51 __wsum ret; 52 53 might_sleep(); 54 stac(); 55 ret = csum_partial_copy_generic((__force void *)src, dst, 56 len, sum, err_ptr, NULL); 57 clac(); 58 59 return ret; 60 } 61 62 /* 63 * This is a version of ip_compute_csum() optimized for IP headers, 64 * which always checksum on 4 octet boundaries. 65 * 66 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 67 * Arnt Gulbrandsen. 68 */ 69 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 70 { 71 unsigned int sum; 72 73 asm volatile("movl (%1), %0 ;\n" 74 "subl $4, %2 ;\n" 75 "jbe 2f ;\n" 76 "addl 4(%1), %0 ;\n" 77 "adcl 8(%1), %0 ;\n" 78 "adcl 12(%1), %0;\n" 79 "1: adcl 16(%1), %0 ;\n" 80 "lea 4(%1), %1 ;\n" 81 "decl %2 ;\n" 82 "jne 1b ;\n" 83 "adcl $0, %0 ;\n" 84 "movl %0, %2 ;\n" 85 "shrl $16, %0 ;\n" 86 "addw %w2, %w0 ;\n" 87 "adcl $0, %0 ;\n" 88 "notl %0 ;\n" 89 "2: ;\n" 90 /* Since the input registers which are loaded with iph and ihl 91 are modified, we must also specify them as outputs, or gcc 92 will assume they contain their original values. */ 93 : "=r" (sum), "=r" (iph), "=r" (ihl) 94 : "1" (iph), "2" (ihl) 95 : "memory"); 96 return (__force __sum16)sum; 97 } 98 99 /* 100 * Fold a partial checksum 101 */ 102 103 static inline __sum16 csum_fold(__wsum sum) 104 { 105 asm("addl %1, %0 ;\n" 106 "adcl $0xffff, %0 ;\n" 107 : "=r" (sum) 108 : "r" ((__force u32)sum << 16), 109 "0" ((__force u32)sum & 0xffff0000)); 110 return (__force __sum16)(~(__force u32)sum >> 16); 111 } 112 113 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 114 __u32 len, __u8 proto, 115 __wsum sum) 116 { 117 asm("addl %1, %0 ;\n" 118 "adcl %2, %0 ;\n" 119 "adcl %3, %0 ;\n" 120 "adcl $0, %0 ;\n" 121 : "=r" (sum) 122 : "g" (daddr), "g"(saddr), 123 "g" ((len + proto) << 8), "0" (sum)); 124 return sum; 125 } 126 127 /* 128 * computes the checksum of the TCP/UDP pseudo-header 129 * returns a 16-bit checksum, already complemented 130 */ 131 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 132 __u32 len, __u8 proto, 133 __wsum sum) 134 { 135 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 136 } 137 138 /* 139 * this routine is used for miscellaneous IP-like checksums, mainly 140 * in icmp.c 141 */ 142 143 static inline __sum16 ip_compute_csum(const void *buff, int len) 144 { 145 return csum_fold(csum_partial(buff, len, 0)); 146 } 147 148 #define _HAVE_ARCH_IPV6_CSUM 149 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 150 const struct in6_addr *daddr, 151 __u32 len, __u8 proto, __wsum sum) 152 { 153 asm("addl 0(%1), %0 ;\n" 154 "adcl 4(%1), %0 ;\n" 155 "adcl 8(%1), %0 ;\n" 156 "adcl 12(%1), %0 ;\n" 157 "adcl 0(%2), %0 ;\n" 158 "adcl 4(%2), %0 ;\n" 159 "adcl 8(%2), %0 ;\n" 160 "adcl 12(%2), %0 ;\n" 161 "adcl %3, %0 ;\n" 162 "adcl %4, %0 ;\n" 163 "adcl $0, %0 ;\n" 164 : "=&r" (sum) 165 : "r" (saddr), "r" (daddr), 166 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) 167 : "memory"); 168 169 return csum_fold(sum); 170 } 171 172 /* 173 * Copy and checksum to user 174 */ 175 #define HAVE_CSUM_COPY_USER 176 static inline __wsum csum_and_copy_to_user(const void *src, 177 void __user *dst, 178 int len, __wsum sum, 179 int *err_ptr) 180 { 181 __wsum ret; 182 183 might_sleep(); 184 if (access_ok(VERIFY_WRITE, dst, len)) { 185 stac(); 186 ret = csum_partial_copy_generic(src, (__force void *)dst, 187 len, sum, NULL, err_ptr); 188 clac(); 189 return ret; 190 } 191 192 if (len) 193 *err_ptr = -EFAULT; 194 195 return (__force __wsum)-1; /* invalid checksum */ 196 } 197 198 #endif /* _ASM_X86_CHECKSUM_32_H */ 199