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#ifndef _I386_CHECKSUM_H

#define _I386_CHECKSUM_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 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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 unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int 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

 *      verify_area().

 */

static __inline__

unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,

                                        int len, int sum)

{

        return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);

}

static __inline__

unsigned int csum_partial_copy_from_user ( const char *src, char *dst,

                                                int len, int sum, int *err_ptr)

{

        return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);

}

/*

 * These are the old (and unsafe) way of doing checksums, a warning message will be

 * printed if they are used and an exeption occurs.

 *

 * these functions should go away after some time.

 */

#define csum_partial_copy_fromuser csum_partial_copy

unsigned int csum_partial_copy( const char *src, char *dst, int len, int 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 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 ipl

           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(sum);

}

/*

 *      Fold a partial checksum

 */

static inline unsigned int csum_fold(unsigned int sum)

{

        __asm__(

                "addl %1, %0            ;\n"

                "adcl $0xffff, %0       ;\n"

                : "=r" (sum)

                : "r" (sum << 16), "0" (sum & 0xffff0000)

        );

        return (~sum) >> 16;

}

static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,

                                                   unsigned long daddr,

                                                   unsigned short len,

                                                   unsigned short proto,

                                                   unsigned int 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"((ntohs(len)<<16)+proto*256), "0"(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__(

                "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));

        return csum_fold(sum);

}

/*

 *      Copy and checksum to user

 */

#define HAVE_CSUM_COPY_USER

static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst,

                                    int len, int sum, int *err_ptr)

{

        if (access_ok(VERIFY_WRITE, dst, len))

                return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);

        if (len)

                *err_ptr = -EFAULT;

        return -1; /* invalid checksum */

}

#endif