Edit File: checksum_32.h
#ifndef _ASM_X86_CHECKSUM_32_H #define _ASM_X86_CHECKSUM_32_H #include <linux/in6.h> #include <asm/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, __wsum sum, int *src_err_ptr, int *dst_err_ptr); /* * 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, __wsum sum) { return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); } static inline __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr) { __wsum ret; might_sleep(); stac(); ret = csum_partial_copy_generic((__force void *)src, dst, len, sum, err_ptr, NULL); clac(); 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, unsigned short 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 */ #define HAVE_CSUM_COPY_USER static inline __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr) { __wsum ret; might_sleep(); if (access_ok(VERIFY_WRITE, dst, len)) { stac(); ret = csum_partial_copy_generic(src, (__force void *)dst, len, sum, NULL, err_ptr); clac(); return ret; } if (len) *err_ptr = -EFAULT; return (__force __wsum)-1; /* invalid checksum */ } #endif /* _ASM_X86_CHECKSUM_32_H */