/* * linux/include/asm-arm/checksum.h * * IP checksum routines * * Copyright (C) Original authors of ../asm-i386/checksum.h * Copyright (C) 1996-1999 Russell King */ #ifndef __ASM_ARM_CHECKSUM_H #define __ASM_ARM_CHECKSUM_H #include <linux/in6.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 */ __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 */ __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum); __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr); /* * Fold a partial checksum without adding pseudo headers */ static inline __sum16 csum_fold(__wsum sum) { __asm__( "add %0, %1, %1, ror #16 @ csum_fold" : "=r" (sum) : "r" (sum) : "cc"); return (__force __sum16)(~(__force u32)sum >> 16); } /* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. */ static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) { unsigned int tmp1; __wsum sum; __asm__ __volatile__( "ldr %0, [%1], #4 @ ip_fast_csum \n\ ldr %3, [%1], #4 \n\ sub %2, %2, #5 \n\ adds %0, %0, %3 \n\ ldr %3, [%1], #4 \n\ adcs %0, %0, %3 \n\ ldr %3, [%1], #4 \n\ 1: adcs %0, %0, %3 \n\ ldr %3, [%1], #4 \n\ tst %2, #15 @ do this carefully \n\ subne %2, %2, #1 @ without destroying \n\ bne 1b @ the carry flag \n\ adcs %0, %0, %3 \n\ adc %0, %0, #0" : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) : "1" (iph), "2" (ihl) : "cc", "memory"); return csum_fold(sum); } static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, unsigned short proto, __wsum sum) { __asm__( "adds %0, %1, %2 @ csum_tcpudp_nofold \n\ adcs %0, %0, %3 \n" #ifdef __ARMEB__ "adcs %0, %0, %4 \n" #else "adcs %0, %0, %4, lsl #8 \n" #endif "adcs %0, %0, %5 \n\ adc %0, %0, #0" : "=&r"(sum) : "r" (sum), "r" (daddr), "r" (saddr), "r" (len), "Ir" (htons(proto)) : "cc"); 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, unsigned short len, unsigned short 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 extern __wsum __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, __be32 proto, __wsum sum); static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __u32 len, unsigned short proto, __wsum sum) { return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), htonl(proto), sum)); } #endif