/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle * Copyright (C) 1999 Silicon Graphics, Inc. * Copyright (C) 2001 Thiemo Seufer. * Copyright (C) 2002 Maciej W. Rozycki */ #ifndef _ASM_CHECKSUM_H #define _ASM_CHECKSUM_H #include <linux/config.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 */ unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum); /* * this is a new version of the above that records errors it finds in *errp, * but continues and zeros the rest of the buffer. */ unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst, int len, unsigned int sum, int *errp); /* * Copy and checksum to user */ #define HAVE_CSUM_COPY_USER static inline unsigned int csum_and_copy_to_user (const unsigned char *src, unsigned char __user *dst, int len, int sum, int *err_ptr) { might_sleep(); sum = csum_partial(src, len, sum); if (copy_to_user(dst, src, len)) { *err_ptr = -EFAULT; return -1; } return sum; } /* * the same as csum_partial, but copies from user space (but on MIPS * we have just one address space, so this is identical to the above) */ unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst, int len, unsigned int sum); /* * Fold a partial checksum without adding pseudo headers */ static inline unsigned short int csum_fold(unsigned int sum) { __asm__( ".set\tnoat\t\t\t# csum_fold\n\t" "sll\t$1,%0,16\n\t" "addu\t%0,$1\n\t" "sltu\t$1,%0,$1\n\t" "srl\t%0,%0,16\n\t" "addu\t%0,$1\n\t" "xori\t%0,0xffff\n\t" ".set\tat" : "=r" (sum) : "0" (sum)); return sum; } /* * 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 unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl) { unsigned int *word = (unsigned int *) iph; unsigned int *stop = word + ihl; unsigned int csum; int carry; csum = word[0]; csum += word[1]; carry = (csum < word[1]); csum += carry; csum += word[2]; carry = (csum < word[2]); csum += carry; csum += word[3]; carry = (csum < word[3]); csum += carry; word += 4; do { csum += *word; carry = (csum < *word); csum += carry; word++; } while (word != stop); return csum_fold(csum); } static inline unsigned int csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int sum) { __asm__( ".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t" #ifdef CONFIG_MIPS32 "addu\t%0, %2\n\t" "sltu\t$1, %0, %2\n\t" "addu\t%0, $1\n\t" "addu\t%0, %3\n\t" "sltu\t$1, %0, %3\n\t" "addu\t%0, $1\n\t" "addu\t%0, %4\n\t" "sltu\t$1, %0, %4\n\t" "addu\t%0, $1\n\t" #endif #ifdef CONFIG_MIPS64 "daddu\t%0, %2\n\t" "daddu\t%0, %3\n\t" "daddu\t%0, %4\n\t" "dsll32\t$1, %0, 0\n\t" "daddu\t%0, $1\n\t" "dsrl32\t%0, %0, 0\n\t" #endif ".set\tat" : "=r" (sum) : "0" (daddr), "r"(saddr), #ifdef __MIPSEL__ "r" (((unsigned long)htons(len)<<16) + proto*256), #else "r" (((unsigned long)(proto)<<16) + len), #endif "r" (sum)); return sum; } /* * computes the checksum of the TCP/UDP pseudo-header * returns a 16-bit checksum, already complemented */ static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len, unsigned short proto, unsigned int 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 unsigned short ip_compute_csum(unsigned char * buff, int len) { return csum_fold(csum_partial(buff, len, 0)); } #define _HAVE_ARCH_IPV6_CSUM static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len, unsigned short proto, unsigned int sum) { __asm__( ".set\tpush\t\t\t# csum_ipv6_magic\n\t" ".set\tnoreorder\n\t" ".set\tnoat\n\t" "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t" "sltu\t$1, %0, %5\n\t" "addu\t%0, $1\n\t" "addu\t%0, %6\t\t\t# csum\n\t" "sltu\t$1, %0, %6\n\t" "lw\t%1, 0(%2)\t\t\t# four words source address\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 4(%2)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 8(%2)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 12(%2)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 0(%3)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 4(%3)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 8(%3)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "lw\t%1, 12(%3)\n\t" "addu\t%0, $1\n\t" "addu\t%0, %1\n\t" "sltu\t$1, %0, %1\n\t" "addu\t%0, $1\t\t\t# Add final carry\n\t" ".set\tpop" : "=r" (sum), "=r" (proto) : "r" (saddr), "r" (daddr), "0" (htonl(len)), "1" (htonl(proto)), "r" (sum)); return csum_fold(sum); } #endif /* _ASM_CHECKSUM_H */