diff options
Diffstat (limited to 'arch/x86/include/asm/checksum_32.h')
| -rw-r--r-- | arch/x86/include/asm/checksum_32.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h new file mode 100644 index 000000000..17da95387 --- /dev/null +++ b/arch/x86/include/asm/checksum_32.h @@ -0,0 +1,186 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_CHECKSUM_32_H +#define _ASM_X86_CHECKSUM_32_H + +#include <linux/in6.h> +#include <linux/uaccess.h> + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +asmlinkage __wsum csum_partial(const void *buff, int len, __wsum sum); + +/* + * the same as csum_partial, but copies from src while it + * checksums, and handles user-space pointer exceptions correctly, when needed. + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ + +asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst, int len); + +/* + * Note: when you get a NULL pointer exception here this means someone + * passed in an incorrect kernel address to one of these functions. + * + * If you use these functions directly please don't forget the + * access_ok(). + */ +static inline __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len) +{ + return csum_partial_copy_generic(src, dst, len); +} + +static inline __wsum csum_and_copy_from_user(const void __user *src, + void *dst, int len) +{ + __wsum ret; + + might_sleep(); + if (!user_access_begin(src, len)) + return 0; + ret = csum_partial_copy_generic((__force void *)src, dst, len); + user_access_end(); + + return ret; +} + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + * + * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by + * Arnt Gulbrandsen. + */ +static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) +{ + unsigned int sum; + + asm volatile("movl (%1), %0 ;\n" + "subl $4, %2 ;\n" + "jbe 2f ;\n" + "addl 4(%1), %0 ;\n" + "adcl 8(%1), %0 ;\n" + "adcl 12(%1), %0;\n" + "1: adcl 16(%1), %0 ;\n" + "lea 4(%1), %1 ;\n" + "decl %2 ;\n" + "jne 1b ;\n" + "adcl $0, %0 ;\n" + "movl %0, %2 ;\n" + "shrl $16, %0 ;\n" + "addw %w2, %w0 ;\n" + "adcl $0, %0 ;\n" + "notl %0 ;\n" + "2: ;\n" + /* Since the input registers which are loaded with iph and ihl + are modified, we must also specify them as outputs, or gcc + will assume they contain their original values. */ + : "=r" (sum), "=r" (iph), "=r" (ihl) + : "1" (iph), "2" (ihl) + : "memory"); + return (__force __sum16)sum; +} + +/* + * Fold a partial checksum + */ + +static inline __sum16 csum_fold(__wsum sum) +{ + asm("addl %1, %0 ;\n" + "adcl $0xffff, %0 ;\n" + : "=r" (sum) + : "r" ((__force u32)sum << 16), + "0" ((__force u32)sum & 0xffff0000)); + return (__force __sum16)(~(__force u32)sum >> 16); +} + +static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, + __u32 len, __u8 proto, + __wsum sum) +{ + asm("addl %1, %0 ;\n" + "adcl %2, %0 ;\n" + "adcl %3, %0 ;\n" + "adcl $0, %0 ;\n" + : "=r" (sum) + : "g" (daddr), "g"(saddr), + "g" ((len + proto) << 8), "0" (sum)); + return sum; +} + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ +static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, + __u32 len, __u8 proto, + __wsum sum) +{ + return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); +} + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ + +static inline __sum16 ip_compute_csum(const void *buff, int len) +{ + return csum_fold(csum_partial(buff, len, 0)); +} + +#define _HAVE_ARCH_IPV6_CSUM +static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, + const struct in6_addr *daddr, + __u32 len, __u8 proto, __wsum sum) +{ + asm("addl 0(%1), %0 ;\n" + "adcl 4(%1), %0 ;\n" + "adcl 8(%1), %0 ;\n" + "adcl 12(%1), %0 ;\n" + "adcl 0(%2), %0 ;\n" + "adcl 4(%2), %0 ;\n" + "adcl 8(%2), %0 ;\n" + "adcl 12(%2), %0 ;\n" + "adcl %3, %0 ;\n" + "adcl %4, %0 ;\n" + "adcl $0, %0 ;\n" + : "=&r" (sum) + : "r" (saddr), "r" (daddr), + "r" (htonl(len)), "r" (htonl(proto)), "0" (sum) + : "memory"); + + return csum_fold(sum); +} + +/* + * Copy and checksum to user + */ +static inline __wsum csum_and_copy_to_user(const void *src, + void __user *dst, + int len) +{ + __wsum ret; + + might_sleep(); + if (!user_access_begin(dst, len)) + return 0; + + ret = csum_partial_copy_generic(src, (__force void *)dst, len); + user_access_end(); + return ret; +} + +#endif /* _ASM_X86_CHECKSUM_32_H */ |