Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * INET         An implementation of the TCP/IP protocol suite for the LINUX

 *              operating system.  INET is implemented using the  BSD Socket

 *              interface as the means of communication with the user level.

 *

 *              MIPS specific IP/TCP/UDP checksumming routines

 *

 * Authors:     Ralf Baechle, <ralf@waldorf-gmbh.de>

 *              Lots of code moved from tcp.c and ip.c; see those files

 *              for more names.

 *

 *              This program is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 *

 */

//#include <net/checksum.h>

#include <linux/types.h>

#include <asm/byteorder.h>

#include <asm/string.h>

#include <asm/uaccess.h>

#include <asm/or32-hf.h>

static inline unsigned short from32to16(unsigned int x)

{

        /* 32 bits --> 16 bits + carry */

        x = (x & 0xffff) + (x >> 16);

        /* 16 bits + carry --> 16 bits including carry */

        x = (x & 0xffff) + (x >> 16);

        return (unsigned short)x;

}

static inline unsigned int do_csum(const unsigned char * buff, int len)

{

        int odd, count;

        unsigned int result = 0;

        if (len <= 0)

                goto out;

        odd = 1 & (unsigned long) buff;

        if (odd) {

                result = be16_to_cpu(*buff);

                len--;

                buff++;

        }

        count = len >> 1;               /* nr of 16-bit words.. */

        if (count) {

                if (2 & (unsigned long) buff) {

                        result += *(unsigned short *) buff;

                        count--;

                        len -= 2;

                        buff += 2;

                }

                count >>= 1;            /* nr of 32-bit words.. */

                if (count) {

                        unsigned int carry = 0;

                        do {

                                unsigned int w = *(unsigned int *) buff;

                                count--;

                                buff += 4;

                                result += carry;

                                result += w;

                                carry = (w > result);

                        } while (count);

                        result += carry;

                        result = (result & 0xffff) + (result >> 16);

                }

                if (len & 2) {

                        result += *(unsigned short *) buff;

                        buff += 2;

                }

        }

        if (len & 1)

                result += le16_to_cpu(*buff);

        result = from32to16(result);

        if (odd)

                result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);

out:

        return result;

}

/*

 * computes a partial checksum, e.g. for TCP/UDP fragments

 */

unsigned int csum_partial(const unsigned char *buff, int len,

                          unsigned int sum)

{

        unsigned int result = do_csum(buff, len);

        /* add in old sum, and carry.. */

        result += sum;

        if(sum > result)

                result += 1;

        return result;

}

/*

 * copy while checksumming, otherwise like csum_partial

 */

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

                                       int len, unsigned int sum)

{

        /*

         * It's 2:30 am and I don't feel like doing it real ...

         * This is lots slower than the real thing (tm)

         */

        sum = csum_partial(src, len, sum);

        memcpy(dst, src, len);

        return sum;

}

/*

 * Copy from userspace and compute checksum.  If we catch an exception

 * then zero the rest of the buffer.

 */

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

                                          int len, unsigned int sum,

                                          int *err_ptr)

{

        int missing;

        phx_warn("CSUM");

        missing = copy_from_user(dst, src, len);

        if (missing) {

                memset(dst + len - missing, 0, missing);

                *err_ptr = -EFAULT;

        }

        return csum_partial(dst, len, sum);

}

/* __PHX__: OLD routines

            move to seperate file

 */

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

                                         int len, unsigned int sum)

{

        __copy_from_user(dst, src, len);

        return csum_partial(dst, len, sum);

}