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_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 __u32 len, __u8 proto, 116 __wsum sum) 117 { 118 asm("addl %1, %0 ;\n" 119 "adcl %2, %0 ;\n" 120 "adcl %3, %0 ;\n" 121 "adcl $0, %0 ;\n" 122 : "=r" (sum) 123 : "g" (daddr), "g"(saddr), 124 "g" ((len + proto) << 8), "0" (sum)); 125 return sum; 126 } 127 128 /* 129 * computes the checksum of the TCP/UDP pseudo-header 130 * returns a 16-bit checksum, already complemented 131 */ 132 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 133 __u32 len, __u8 proto, 134 __wsum sum) 135 { 136 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 137 } 138 139 /* 140 * this routine is used for miscellaneous IP-like checksums, mainly 141 * in icmp.c 142 */ 143 144 static inline __sum16 ip_compute_csum(const void *buff, int len) 145 { 146 return csum_fold(csum_partial(buff, len, 0)); 147 } 148 149 #define _HAVE_ARCH_IPV6_CSUM 150 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, 151 const struct in6_addr *daddr, 152 __u32 len, __u8 proto, __wsum sum) 153 { 154 asm("addl 0(%1), %0 ;\n" 155 "adcl 4(%1), %0 ;\n" 156 "adcl 8(%1), %0 ;\n" 157 "adcl 12(%1), %0 ;\n" 158 "adcl 0(%2), %0 ;\n" 159 "adcl 4(%2), %0 ;\n" 160 "adcl 8(%2), %0 ;\n" 161 "adcl 12(%2), %0 ;\n" 162 "adcl %3, %0 ;\n" 163 "adcl %4, %0 ;\n" 164 "adcl $0, %0 ;\n" 165 : "=&r" (sum) 166 : "r" (saddr), "r" (daddr), 167 "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) 168 : "memory"); 169 170 return csum_fold(sum); 171 } 172 173 /* 174 * Copy and checksum to user 175 */ 176 #define HAVE_CSUM_COPY_USER 177 static inline __wsum csum_and_copy_to_user(const void *src, 178 void __user *dst, 179 int len, __wsum sum, 180 int *err_ptr) 181 { 182 __wsum ret; 183 184 might_sleep(); 185 if (access_ok(dst, len)) { 186 stac(); 187 ret = csum_partial_copy_generic(src, (__force void *)dst, 188 len, sum, NULL, err_ptr); 189 clac(); 190 return ret; 191 } 192 193 if (len) 194 *err_ptr = -EFAULT; 195 196 return (__force __wsum)-1; /* invalid checksum */ 197 } 198 199 #endif /* _ASM_X86_CHECKSUM_32_H */ 200