1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_X86_CHECKSUM_32_H 3 #define _ASM_X86_CHECKSUM_32_H 4 5 #include <linux/in6.h> 6 #include <linux/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_and_copy_from_user(const void __user *src, 48 void *dst, int len, 49 __wsum sum, int *err_ptr) 50 { 51 __wsum ret; 52 53 might_sleep(); 54 if (!user_access_begin(src, len)) { 55 if (len) 56 *err_ptr = -EFAULT; 57 return sum; 58 } 59 ret = csum_partial_copy_generic((__force void *)src, dst, 60 len, sum, err_ptr, NULL); 61 user_access_end(); 62 63 return ret; 64 } 65 66 /* 67 * This is a version of ip_compute_csum() optimized for IP headers, 68 * which always checksum on 4 octet boundaries. 69 * 70 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by 71 * Arnt Gulbrandsen. 72 */ 73 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 74 { 75 unsigned int sum; 76 77 asm volatile("movl (%1), %0 ;\n" 78 "subl $4, %2 ;\n" 79 "jbe 2f ;\n" 80 "addl 4(%1), %0 ;\n" 81 "adcl 8(%1), %0 ;\n" 82 "adcl 12(%1), %0;\n" 83 "1: adcl 16(%1), %0 ;\n" 84 "lea 4(%1), %1 ;\n" 85 "decl %2 ;\n" 86 "jne 1b ;\n" 87 "adcl $0, %0 ;\n" 88 "movl %0, %2 ;\n" 89 "shrl $16, %0 ;\n" 90 "addw %w2, %w0 ;\n" 91 "adcl $0, %0 ;\n" 92 "notl %0 ;\n" 93 "2: ;\n" 94 /* Since the input registers which are loaded with iph and ihl 95 are modified, we must also specify them as outputs, or gcc 96 will assume they contain their original values. */ 97 : "=r" (sum), "=r" (iph), "=r" (ihl) 98 : "1" (iph), "2" (ihl) 99 : "memory"); 100 return (__force __sum16)sum; 101 } 102 103 /* 104 * Fold a partial checksum 105 */ 106 107 static inline __sum16 csum_fold(__wsum sum) 108 { 109 asm("addl %1, %0 ;\n" 110 "adcl $0xffff, %0 ;\n" 111 : "=r" (sum) 112 : "r" ((__force u32)sum << 16), 113 "0" ((__force u32)sum & 0xffff0000)); 114 return (__force __sum16)(~(__force u32)sum >> 16); 115 } 116 117 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 118 __u32 len, __u8 proto, 119 __wsum sum) 120 { 121 asm("addl %1, %0 ;\n" 122 "adcl %2, %0 ;\n" 123 "adcl %3, %0 ;\n" 124 "adcl $0, %0 ;\n" 125 : "=r" (sum) 126 : "g" (daddr), "g"(saddr), 127 "g" ((len + proto) << 8), "0" (sum)); 128 return sum; 129 } 130 131 /* 132 * computes the checksum of the TCP/UDP pseudo-header 133 * returns a 16-bit checksum, already complemented 134 */ 135 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 136 __u32 len, __u8 proto, 137 __wsum sum) 138 { 139 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 140 } 141 142 /* 143 * this routine is used for miscellaneous IP-like checksums, mainly 144 * in icmp.c 145 */ 146 147 static inline __sum16 ip_compute_csum(const void *buff, int len) 148 { 149 return csum_fold(csum_partial(buff, len, 0)); 150 } 151 152 #define _HAVE_ARCH_IPV6_CSUM 153 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 154 const struct in6_addr *daddr, 155 __u32 len, __u8 proto, __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 static inline __wsum csum_and_copy_to_user(const void *src, 180 void __user *dst, 181 int len, __wsum sum, 182 int *err_ptr) 183 { 184 __wsum ret; 185 186 might_sleep(); 187 if (user_access_begin(dst, len)) { 188 ret = csum_partial_copy_generic(src, (__force void *)dst, 189 len, sum, NULL, err_ptr); 190 user_access_end(); 191 return ret; 192 } 193 194 if (len) 195 *err_ptr = -EFAULT; 196 197 return (__force __wsum)-1; /* invalid checksum */ 198 } 199 200 #endif /* _ASM_X86_CHECKSUM_32_H */ 201