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| 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, int len); |
| 31 | |
| 32 | /* |
| 33 | * Note: when you get a NULL pointer exception here this means someone |
| 34 | * passed in an incorrect kernel address to one of these functions. |
| 35 | * |
| 36 | * If you use these functions directly please don't forget the |
| 37 | * access_ok(). |
| 38 | */ |
| 39 | static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) |
| 40 | { |
| 41 | return csum_partial_copy_generic(src, dst, len); |
| 42 | } |
| 43 | |
| 44 | static inline __wsum csum_and_copy_from_user(const void __user *src, |
| 45 | void *dst, int len) |
| 46 | { |
| 47 | __wsum ret; |
| 48 | |
| 49 | might_sleep(); |
| 50 | if (!user_access_begin(src, len)) |
| 51 | return 0; |
| 52 | ret = csum_partial_copy_generic((__force void *)src, dst, len); |
| 53 | user_access_end(); |
| 54 | |
| 55 | return ret; |
| 56 | } |
| 57 | |
| 58 | /* |
| 59 | * This is a version of ip_compute_csum() optimized for IP headers, |
| 60 | * which always checksum on 4 octet boundaries. |
| 61 | * |
| 62 | * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by |
| 63 | * Arnt Gulbrandsen. |
| 64 | */ |
| 65 | static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) |
| 66 | { |
| 67 | unsigned int sum; |
| 68 | |
| 69 | asm volatile("movl (%1), %0 ;\n" |
| 70 | "subl $4, %2 ;\n" |
| 71 | "jbe 2f ;\n" |
| 72 | "addl 4(%1), %0 ;\n" |
| 73 | "adcl 8(%1), %0 ;\n" |
| 74 | "adcl 12(%1), %0;\n" |
| 75 | "1: adcl 16(%1), %0 ;\n" |
| 76 | "lea 4(%1), %1 ;\n" |
| 77 | "decl %2 ;\n" |
| 78 | "jne 1b ;\n" |
| 79 | "adcl $0, %0 ;\n" |
| 80 | "movl %0, %2 ;\n" |
| 81 | "shrl $16, %0 ;\n" |
| 82 | "addw %w2, %w0 ;\n" |
| 83 | "adcl $0, %0 ;\n" |
| 84 | "notl %0 ;\n" |
| 85 | "2: ;\n" |
| 86 | /* Since the input registers which are loaded with iph and ihl |
| 87 | are modified, we must also specify them as outputs, or gcc |
| 88 | will assume they contain their original values. */ |
| 89 | : "=r" (sum), "=r" (iph), "=r" (ihl) |
| 90 | : "1" (iph), "2" (ihl) |
| 91 | : "memory"); |
| 92 | return (__force __sum16)sum; |
| 93 | } |
| 94 | |
| 95 | /* |
| 96 | * Fold a partial checksum |
| 97 | */ |
| 98 | |
| 99 | static inline __sum16 csum_fold(__wsum sum) |
| 100 | { |
| 101 | asm("addl %1, %0 ;\n" |
| 102 | "adcl $0xffff, %0 ;\n" |
| 103 | : "=r" (sum) |
| 104 | : "r" ((__force u32)sum << 16), |
| 105 | "0" ((__force u32)sum & 0xffff0000)); |
| 106 | return (__force __sum16)(~(__force u32)sum >> 16); |
| 107 | } |
| 108 | |
| 109 | static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, |
| 110 | __u32 len, __u8 proto, |
| 111 | __wsum sum) |
| 112 | { |
| 113 | asm("addl %1, %0 ;\n" |
| 114 | "adcl %2, %0 ;\n" |
| 115 | "adcl %3, %0 ;\n" |
| 116 | "adcl $0, %0 ;\n" |
| 117 | : "=r" (sum) |
| 118 | : "g" (daddr), "g"(saddr), |
| 119 | "g" ((len + proto) << 8), "0" (sum)); |
| 120 | return sum; |
| 121 | } |
| 122 | |
| 123 | /* |
| 124 | * computes the checksum of the TCP/UDP pseudo-header |
| 125 | * returns a 16-bit checksum, already complemented |
| 126 | */ |
| 127 | static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, |
| 128 | __u32 len, __u8 proto, |
| 129 | __wsum sum) |
| 130 | { |
| 131 | return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); |
| 132 | } |
| 133 | |
| 134 | /* |
| 135 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 136 | * in icmp.c |
| 137 | */ |
| 138 | |
| 139 | static inline __sum16 ip_compute_csum(const void *buff, int len) |
| 140 | { |
| 141 | return csum_fold(csum_partial(buff, len, 0)); |
| 142 | } |
| 143 | |
| 144 | #define _HAVE_ARCH_IPV6_CSUM |
| 145 | static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, |
| 146 | const struct in6_addr *daddr, |
| 147 | __u32 len, __u8 proto, __wsum sum) |
| 148 | { |
| 149 | asm("addl 0(%1), %0 ;\n" |
| 150 | "adcl 4(%1), %0 ;\n" |
| 151 | "adcl 8(%1), %0 ;\n" |
| 152 | "adcl 12(%1), %0 ;\n" |
| 153 | "adcl 0(%2), %0 ;\n" |
| 154 | "adcl 4(%2), %0 ;\n" |
| 155 | "adcl 8(%2), %0 ;\n" |
| 156 | "adcl 12(%2), %0 ;\n" |
| 157 | "adcl %3, %0 ;\n" |
| 158 | "adcl %4, %0 ;\n" |
| 159 | "adcl $0, %0 ;\n" |
| 160 | : "=&r" (sum) |
| 161 | : "r" (saddr), "r" (daddr), |
| 162 | "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) |
| 163 | : "memory"); |
| 164 | |
| 165 | return csum_fold(sum); |
| 166 | } |
| 167 | |
| 168 | /* |
| 169 | * Copy and checksum to user |
| 170 | */ |
| 171 | static inline __wsum csum_and_copy_to_user(const void *src, |
| 172 | void __user *dst, |
| 173 | int len) |
| 174 | { |
| 175 | __wsum ret; |
| 176 | |
| 177 | might_sleep(); |
| 178 | if (!user_access_begin(dst, len)) |
| 179 | return 0; |
| 180 | |
| 181 | ret = csum_partial_copy_generic(src, (__force void *)dst, len); |
| 182 | user_access_end(); |
| 183 | return ret; |
| 184 | } |
| 185 | |
| 186 | #endif /* _ASM_X86_CHECKSUM_32_H */ |
| 187 |
Warning: This file is not a C or C++ file. It does not have highlighting.