root/include/asm-m68k/checksum.h

INCLUDED FROM

DEFINITIONS

1. ip_fast_csum
2. csum_fold
3. csum_tcpudp_nofold
4. csum_tcpudp_magic
5. ip_compute_csum
6. csum_ipv6_magic

#ifndef _M68K_CHECKSUM_H
#define _M68K_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
 *
 * here even more important to align src and dst on a 32-bit (or even
 * better 64-bit) boundary
 */

extern __wsum csum_partial_copy_from_user(const void __user *src,
                                                void *dst,
                                                int len, __wsum sum,
                                                int *csum_err);

extern __wsum csum_partial_copy_nocheck(const void *src,
                                              void *dst, int len,
                                              __wsum sum);

/*
 *      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 sum = 0;
        unsigned long tmp;

        __asm__ ("subqw #1,%2\n"
                 "1:\t"
                 "movel %1@+,%3\n\t"
                 "addxl %3,%0\n\t"
                 "dbra  %2,1b\n\t"
                 "movel %0,%3\n\t"
                 "swap  %3\n\t"
                 "addxw %3,%0\n\t"
                 "clrw  %3\n\t"
                 "addxw %3,%0\n\t"
                 : "=d" (sum), "=&a" (iph), "=&d" (ihl), "=&d" (tmp)
                 : "0" (sum), "1" (iph), "2" (ihl)
                 : "memory");
        return (__force __sum16)~sum;
}

/*
 *      Fold a partial checksum
 */

static inline __sum16 csum_fold(__wsum sum)
{
        unsigned int tmp = (__force u32)sum;
        __asm__("swap %1\n\t"
                "addw %1, %0\n\t"
                "clrw %1\n\t"
                "addxw %1, %0"
                : "=&d" (sum), "=&d" (tmp)
                : "0" (sum), "1" (tmp));
        return (__force __sum16)~sum;
}


static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
                  unsigned short proto, __wsum sum)
{
        __asm__ ("addl  %2,%0\n\t"
                 "addxl %3,%0\n\t"
                 "addxl %4,%0\n\t"
                 "clrl %1\n\t"
                 "addxl %1,%0"
                 : "=&d" (sum), "=d" (saddr)
                 : "g" (daddr), "1" (saddr), "d" (len + proto),
                   "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, 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
static __inline__ __sum16
csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
                __u32 len, unsigned short proto, __wsum sum)
{
        register unsigned long tmp;
        __asm__("addl %2@,%0\n\t"
                "movel %2@(4),%1\n\t"
                "addxl %1,%0\n\t"
                "movel %2@(8),%1\n\t"
                "addxl %1,%0\n\t"
                "movel %2@(12),%1\n\t"
                "addxl %1,%0\n\t"
                "movel %3@,%1\n\t"
                "addxl %1,%0\n\t"
                "movel %3@(4),%1\n\t"
                "addxl %1,%0\n\t"
                "movel %3@(8),%1\n\t"
                "addxl %1,%0\n\t"
                "movel %3@(12),%1\n\t"
                "addxl %1,%0\n\t"
                "addxl %4,%0\n\t"
                "clrl %1\n\t"
                "addxl %1,%0"
                : "=&d" (sum), "=&d" (tmp)
                : "a" (saddr), "a" (daddr), "d" (len + proto),
                  "0" (sum));

        return csum_fold(sum);
}

#endif /* _M68K_CHECKSUM_H */