[apple/xnu.git] / bsd / netinet / in_cksum.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1988, 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)in_cksum.c	8.1 (Berkeley) 6/10/93
 */

#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/kdebug.h>

#define DBG_FNC_IN_CKSUM	NETDBG_CODE(DBG_NETIP, (3 << 8))

/*
 * Checksum routine for Internet Protocol family headers (Portable Version).
 *
 * This routine is very heavily used in the network
 * code and should be modified for each CPU to be as fast as possible.
 */

union s_util {
        char    c[2];
        u_short s;
};

union l_util {
        u_int16_t s[2];
        u_int32_t l;   
};

union q_util {
        u_int16_t s[4];
        u_int32_t l[2];
        u_int64_t q;
};    

#define ADDCARRY(x)  (x > 65535 ? x -= 65535 : x)

#define REDUCE32                                                          \
    {                                                                     \
        q_util.q = sum;                                                   \
        sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3];      \
    }
#define REDUCE16                                                          \
    {                                                                     \
        q_util.q = sum;                                                   \
        l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
        sum = l_util.s[0] + l_util.s[1];                                  \
        ADDCARRY(sum);                                                    \
    }

#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}

                
#if defined(ppc)

__inline unsigned short
in_addword(u_short a, u_short b)
{
        union l_util l_util;   
	u_int32_t sum = a + b;
	REDUCE;
	return (sum);
}

__inline unsigned short
in_pseudo(u_int a, u_int b, u_int c)
{
        u_int64_t sum;
        union q_util q_util;
        union l_util l_util;   

        sum = (u_int64_t) a + b + c;
        REDUCE16;
        return (sum);

}

int
in_cksum(m, len)
	register struct mbuf *m;
	register int len;
{
	register u_short *w;
	register int sum = 0;
	register int mlen = 0;
	int starting_on_odd  = 0;


	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);

	for (;m && len; m = m->m_next) {
		if (m->m_len == 0)
			continue;
		mlen = m->m_len;
		w = mtod(m, u_short *);

		if (len < mlen)
			mlen = len;

		sum = xsum_assym(w, mlen, sum, starting_on_odd);
		len -= mlen;
		if (mlen & 0x1)
		{
		    if (starting_on_odd)
			starting_on_odd = 0;
		    else
			starting_on_odd = 1;
		}
	}

	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
	return (~sum & 0xffff);
}

u_short
in_cksum_skip(m, len, skip)
        register struct mbuf *m;
        register int len;
        register int skip;
{
	register u_short *w;
	register int sum = 0;
	register int mlen = 0;
	int starting_on_odd  = 0;

	len -= skip;
        for (; skip && m; m = m->m_next) {
                if (m->m_len > skip) {
                        mlen = m->m_len - skip;
			w = (u_short *)(m->m_data+skip);
                        goto skip_start;
                } else {    
                        skip -= m->m_len;
                }
        }
	for (;m && len; m = m->m_next) {
		if (m->m_len == 0)
			continue;
		mlen = m->m_len;
		w = mtod(m, u_short *);

skip_start:
		if (len < mlen)
			mlen = len;
		sum = xsum_assym(w, mlen, sum, starting_on_odd);
		len -= mlen;
		if (mlen & 0x1)
		{
		    if (starting_on_odd)
			starting_on_odd = 0;
		    else
			starting_on_odd = 1;
		}
	}

	return (~sum & 0xffff);
}
#else

u_short 
in_addword(u_short a, u_short b)
{       
        union l_util l_util;   
        u_int32_t sum = a + b;
        REDUCE(sum);
        return (sum);
}       

u_short
in_pseudo(u_int a, u_int b, u_int c)
{
        u_int64_t sum;  
        union q_util q_util;
        union l_util l_util;   

        sum = (u_int64_t) a + b + c;
        REDUCE16;
        return (sum);
}


int
in_cksum(m, len)
	register struct mbuf *m;
	register int len;
{
	register u_short *w;
	register int sum = 0;
	register int mlen = 0;
	int byte_swapped = 0;
	union s_util s_util;
	union l_util l_util;   

	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);

	for (;m && len; m = m->m_next) {
		if (m->m_len == 0)
			continue;
		w = mtod(m, u_short *);
		if (mlen == -1) {
			/*
			 * The first byte of this mbuf is the continuation
			 * of a word spanning between this mbuf and the
			 * last mbuf.
			 *
			 * s_util.c[0] is already saved when scanning previous
			 * mbuf.
			 */
			s_util.c[1] = *(char *)w;
			sum += s_util.s;
			w = (u_short *)((char *)w + 1);
			mlen = m->m_len - 1;
			len--;
		} else
			mlen = m->m_len;
		if (len < mlen)
			mlen = len;
		len -= mlen;
		/*
		 * Force to even boundary.
		 */
		if ((1 & (int) w) && (mlen > 0)) {
			REDUCE;
			sum <<= 8;
			s_util.c[0] = *(u_char *)w;
			w = (u_short *)((char *)w + 1);
			mlen--;
			byte_swapped = 1;
		}
		/*
		 * Unroll the loop to make overhead from
		 * branches &c small.
		 */
		while ((mlen -= 32) >= 0) {
			sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
			sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
			sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
			sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
			w += 16;
		}
		mlen += 32;
		while ((mlen -= 8) >= 0) {
			sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
			w += 4;
		}
		mlen += 8;
		if (mlen == 0 && byte_swapped == 0)
			continue;
		REDUCE;
		while ((mlen -= 2) >= 0) {
			sum += *w++;
		}
		if (byte_swapped) {
			REDUCE;
			sum <<= 8;
			byte_swapped = 0;
			if (mlen == -1) {
				s_util.c[1] = *(char *)w;
				sum += s_util.s;
				mlen = 0;
			} else
				mlen = -1;
		} else if (mlen == -1)
			s_util.c[0] = *(char *)w;
	}
	if (len)
		printf("cksum: out of data\n");
	if (mlen == -1) {
		/* The last mbuf has odd # of bytes. Follow the
		   standard (the odd byte may be shifted left by 8 bits
		   or not as determined by endian-ness of the machine) */
		s_util.c[1] = 0;
		sum += s_util.s;
	}
	REDUCE;
	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
	return (~sum & 0xffff);
}

int
in_cksum_skip(m, len, skip)
	register struct mbuf *m;
	register u_short len;
	register u_short skip;
{
	register u_short *w;
	register int sum = 0;
	register int mlen = 0;
	int byte_swapped = 0;
	union s_util s_util;
	union l_util l_util;   

	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_START, len,0,0,0,0);

	len -= skip;
        for (; skip && m; m = m->m_next) {
                if (m->m_len > skip) {
                        mlen = m->m_len - skip;
			w = (u_short *)(m->m_data+skip);
                        goto skip_start;
                } else {    
                        skip -= m->m_len;
                }
        }
	for (;m && len; m = m->m_next) {
		if (m->m_len == 0)
			continue;
		w = mtod(m, u_short *);

		if (mlen == -1) {
			/*
			 * The first byte of this mbuf is the continuation
			 * of a word spanning between this mbuf and the
			 * last mbuf.
			 *
			 * s_util.c[0] is already saved when scanning previous
			 * mbuf.
			 */
			s_util.c[1] = *(char *)w;
			sum += s_util.s;
			w = (u_short *)((char *)w + 1);
			mlen = m->m_len - 1;
			len--;
		} else {
		  mlen = m->m_len;
		}
skip_start:
		if (len < mlen)
		    mlen = len;

		len -= mlen;
		/*
		 * Force to even boundary.
		 */
		if ((1 & (int) w) && (mlen > 0)) {
			REDUCE;
			sum <<= 8;
			s_util.c[0] = *(u_char *)w;
			w = (u_short *)((char *)w + 1);
			mlen--;
			byte_swapped = 1;
		}
		/*
		 * Unroll the loop to make overhead from
		 * branches &c small.
		 */
		while ((mlen -= 32) >= 0) {
			sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
			sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
			sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
			sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
			w += 16;
		}
		mlen += 32;
		while ((mlen -= 8) >= 0) {
			sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
			w += 4;
		}
		mlen += 8;
		if (mlen == 0 && byte_swapped == 0)
			continue;
		REDUCE;
		while ((mlen -= 2) >= 0) {
			sum += *w++;
		}
		if (byte_swapped) {
			REDUCE;
			sum <<= 8;
			byte_swapped = 0;
			if (mlen == -1) {
				s_util.c[1] = *(char *)w;
				sum += s_util.s;
				mlen = 0;
			} else
				mlen = -1;
		} else if (mlen == -1)
			s_util.c[0] = *(char *)w;
	}
	if (len)
		printf("cksum: out of data\n");
	if (mlen == -1) {
		/* The last mbuf has odd # of bytes. Follow the
		   standard (the odd byte may be shifted left by 8 bits
		   or not as determined by endian-ness of the machine) */
		s_util.c[1] = 0;
		sum += s_util.s;
	}
	REDUCE;
	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);
	return (~sum & 0xffff);
}

#endif
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
43866e37	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
1c79356b	7	*
43866e37 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
43866e37 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
1c79356b A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/*
	26	* Copyright (c) 1988, 1992, 1993
	27	* The Regents of the University of California. All rights reserved.
	28	*
	29	* Redistribution and use in source and binary forms, with or without
	30	* modification, are permitted provided that the following conditions
	31	* are met:
	32	* 1. Redistributions of source code must retain the above copyright
	33	* notice, this list of conditions and the following disclaimer.
	34	* 2. Redistributions in binary form must reproduce the above copyright
	35	* notice, this list of conditions and the following disclaimer in the
	36	* documentation and/or other materials provided with the distribution.
	37	* 3. All advertising materials mentioning features or use of this software
	38	* must display the following acknowledgement:
	39	* This product includes software developed by the University of
	40	* California, Berkeley and its contributors.
	41	* 4. Neither the name of the University nor the names of its contributors
	42	* may be used to endorse or promote products derived from this software
	43	* without specific prior written permission.
	44	*
	45	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	46	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	47	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	48	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	49	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	50	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	51	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	52	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	53	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	54	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	55	* SUCH DAMAGE.
	56	*
	57	* @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
	58	*/
	59
	60	#include <sys/param.h>
	61	#include <sys/mbuf.h>
	62	#include <sys/kdebug.h>
	63
	64	#define DBG_FNC_IN_CKSUM NETDBG_CODE(DBG_NETIP, (3 << 8))
	65
	66	/*
	67	* Checksum routine for Internet Protocol family headers (Portable Version).
	68	*
	69	* This routine is very heavily used in the network
	70	* code and should be modified for each CPU to be as fast as possible.
	71	*/
	72
0b4e3aa0 A	73	union s_util {
	74	char c[2];
	75	u_short s;
	76	};
1c79356b	77
0b4e3aa0 A	78	union l_util {
	79	u_int16_t s[2];
	80	u_int32_t l;
	81	};
1c79356b	82
0b4e3aa0 A	83	union q_util {
	84	u_int16_t s[4];
	85	u_int32_t l[2];
	86	u_int64_t q;
	87	};
	88
	89	#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
	90
	91	#define REDUCE32 \
	92	{ \
	93	q_util.q = sum; \
	94	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	95	}
	96	#define REDUCE16 \
	97	{ \
	98	q_util.q = sum; \
	99	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	100	sum = l_util.s[0] + l_util.s[1]; \
	101	ADDCARRY(sum); \
	102	}
	103
	104	#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
	105
	106
1c79356b A	107	#if defined(ppc)
1c79356b A	108
0b4e3aa0 A	109	__inline unsigned short
	110	in_addword(u_short a, u_short b)
	111	{
	112	union l_util l_util;
	113	u_int32_t sum = a + b;
	114	REDUCE;
	115	return (sum);
	116	}
	117
	118	__inline unsigned short
	119	in_pseudo(u_int a, u_int b, u_int c)
	120	{
	121	u_int64_t sum;
	122	union q_util q_util;
	123	union l_util l_util;
	124
	125	sum = (u_int64_t) a + b + c;
	126	REDUCE16;
	127	return (sum);
	128
	129	}
	130
1c79356b A	131	int
	132	in_cksum(m, len)
	133	register struct mbuf *m;
	134	register int len;
	135	{
	136	register u_short *w;
	137	register int sum = 0;
	138	register int mlen = 0;
	139	int starting_on_odd = 0;
	140
	141
	142	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	143
	144	for (;m && len; m = m->m_next) {
	145	if (m->m_len == 0)
	146	continue;
	147	mlen = m->m_len;
	148	w = mtod(m, u_short *);
	149
	150	if (len < mlen)
	151	mlen = len;
	152
	153	sum = xsum_assym(w, mlen, sum, starting_on_odd);
	154	len -= mlen;
	155	if (mlen & 0x1)
	156	{
	157	if (starting_on_odd)
	158	starting_on_odd = 0;
	159	else
	160	starting_on_odd = 1;
	161	}
	162	}
	163
	164	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	165	return (~sum & 0xffff);
	166	}
	167
0b4e3aa0 A	168	u_short
	169	in_cksum_skip(m, len, skip)
	170	register struct mbuf *m;
	171	register int len;
	172	register int skip;
	173	{
	174	register u_short *w;
	175	register int sum = 0;
	176	register int mlen = 0;
	177	int starting_on_odd = 0;
	178
	179	len -= skip;
	180	for (; skip && m; m = m->m_next) {
	181	if (m->m_len > skip) {
	182	mlen = m->m_len - skip;
	183	w = (u_short *)(m->m_data+skip);
	184	goto skip_start;
	185	} else {
	186	skip -= m->m_len;
	187	}
	188	}
	189	for (;m && len; m = m->m_next) {
	190	if (m->m_len == 0)
	191	continue;
	192	mlen = m->m_len;
	193	w = mtod(m, u_short *);
	194
765c9de3	195	skip_start:
0b4e3aa0 A	196	if (len < mlen)
0b4e3aa0 A	197	mlen = len;
0b4e3aa0 A	198	sum = xsum_assym(w, mlen, sum, starting_on_odd);
	199	len -= mlen;
	200	if (mlen & 0x1)
	201	{
	202	if (starting_on_odd)
	203	starting_on_odd = 0;
	204	else
	205	starting_on_odd = 1;
	206	}
	207	}
	208
	209	return (~sum & 0xffff);
	210	}
1c79356b A	211	#else
1c79356b A	212
0b4e3aa0 A	213	u_short
	214	in_addword(u_short a, u_short b)
	215	{
	216	union l_util l_util;
	217	u_int32_t sum = a + b;
	218	REDUCE(sum);
	219	return (sum);
	220	}
1c79356b	221
0b4e3aa0 A	222	u_short
	223	in_pseudo(u_int a, u_int b, u_int c)
	224	{
	225	u_int64_t sum;
	226	union q_util q_util;
	227	union l_util l_util;
1c79356b	228
0b4e3aa0 A	229	sum = (u_int64_t) a + b + c;
	230	REDUCE16;
	231	return (sum);
	232	}
1c79356b A	233
	234
	235	int
	236	in_cksum(m, len)
	237	register struct mbuf *m;
	238	register int len;
	239	{
	240	register u_short *w;
	241	register int sum = 0;
	242	register int mlen = 0;
	243	int byte_swapped = 0;
0b4e3aa0 A	244	union s_util s_util;
0b4e3aa0 A	245	union l_util l_util;
1c79356b A	246
	247	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	248
	249	for (;m && len; m = m->m_next) {
	250	if (m->m_len == 0)
	251	continue;
	252	w = mtod(m, u_short *);
	253	if (mlen == -1) {
	254	/*
	255	* The first byte of this mbuf is the continuation
	256	* of a word spanning between this mbuf and the
	257	* last mbuf.
	258	*
	259	* s_util.c[0] is already saved when scanning previous
	260	* mbuf.
	261	*/
	262	s_util.c[1] = (char )w;
	263	sum += s_util.s;
	264	w = (u_short )((char )w + 1);
	265	mlen = m->m_len - 1;
	266	len--;
	267	} else
	268	mlen = m->m_len;
	269	if (len < mlen)
	270	mlen = len;
	271	len -= mlen;
	272	/*
	273	* Force to even boundary.
	274	*/
	275	if ((1 & (int) w) && (mlen > 0)) {
	276	REDUCE;
	277	sum <<= 8;
	278	s_util.c[0] = (u_char )w;
	279	w = (u_short )((char )w + 1);
	280	mlen--;
	281	byte_swapped = 1;
	282	}
	283	/*
	284	* Unroll the loop to make overhead from
	285	* branches &c small.
	286	*/
	287	while ((mlen -= 32) >= 0) {
	288	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	289	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
0b4e3aa0 A	290	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	291	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	292	w += 16;
	293	}
	294	mlen += 32;
	295	while ((mlen -= 8) >= 0) {
	296	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	297	w += 4;
	298	}
	299	mlen += 8;
	300	if (mlen == 0 && byte_swapped == 0)
	301	continue;
	302	REDUCE;
	303	while ((mlen -= 2) >= 0) {
	304	sum += *w++;
	305	}
	306	if (byte_swapped) {
	307	REDUCE;
	308	sum <<= 8;
	309	byte_swapped = 0;
	310	if (mlen == -1) {
	311	s_util.c[1] = (char )w;
	312	sum += s_util.s;
	313	mlen = 0;
	314	} else
	315	mlen = -1;
	316	} else if (mlen == -1)
	317	s_util.c[0] = (char )w;
	318	}
	319	if (len)
	320	printf("cksum: out of data\n");
	321	if (mlen == -1) {
	322	/* The last mbuf has odd # of bytes. Follow the
	323	standard (the odd byte may be shifted left by 8 bits
	324	or not as determined by endian-ness of the machine) */
	325	s_util.c[1] = 0;
	326	sum += s_util.s;
	327	}
	328	REDUCE;
	329	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	330	return (~sum & 0xffff);
	331	}
	332
	333	int
	334	in_cksum_skip(m, len, skip)
	335	register struct mbuf *m;
	336	register u_short len;
	337	register u_short skip;
	338	{
	339	register u_short *w;
	340	register int sum = 0;
	341	register int mlen = 0;
	342	int byte_swapped = 0;
	343	union s_util s_util;
	344	union l_util l_util;
	345
	346	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	347
	348	len -= skip;
	349	for (; skip && m; m = m->m_next) {
	350	if (m->m_len > skip) {
	351	mlen = m->m_len - skip;
	352	w = (u_short *)(m->m_data+skip);
	353	goto skip_start;
354	} else {
355	skip -= m->m_len;
356	}
357	}
358	for (;m && len; m = m->m_next) {
359	if (m->m_len == 0)
360	continue;
361	w = mtod(m, u_short *);
362
363	if (mlen == -1) {
364	/*
365	* The first byte of this mbuf is the continuation
366	* of a word spanning between this mbuf and the
367	* last mbuf.
368	*
369	* s_util.c[0] is already saved when scanning previous
370	* mbuf.
371	*/
372	s_util.c[1] = (char )w;
373	sum += s_util.s;
374	w = (u_short )((char )w + 1);
375	mlen = m->m_len - 1;
376	len--;
377	} else {
378	mlen = m->m_len;
379	}
0b4e3aa0	380	skip_start:
765c9de3 A	381	if (len < mlen)
765c9de3 A	382	mlen = len;
0b4e3aa0 A	383
	384	len -= mlen;
	385	/*
	386	* Force to even boundary.
	387	*/
	388	if ((1 & (int) w) && (mlen > 0)) {
	389	REDUCE;
	390	sum <<= 8;
	391	s_util.c[0] = (u_char )w;
	392	w = (u_short )((char )w + 1);
	393	mlen--;
	394	byte_swapped = 1;
	395	}
	396	/*
	397	* Unroll the loop to make overhead from
	398	* branches &c small.
	399	*/
	400	while ((mlen -= 32) >= 0) {
	401	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	402	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
1c79356b A	403	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	404	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	405	w += 16;
	406	}
	407	mlen += 32;
	408	while ((mlen -= 8) >= 0) {
	409	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	410	w += 4;
	411	}
	412	mlen += 8;
	413	if (mlen == 0 && byte_swapped == 0)
	414	continue;
	415	REDUCE;
	416	while ((mlen -= 2) >= 0) {
	417	sum += *w++;
	418	}
	419	if (byte_swapped) {
	420	REDUCE;
	421	sum <<= 8;
	422	byte_swapped = 0;
	423	if (mlen == -1) {
	424	s_util.c[1] = (char )w;
	425	sum += s_util.s;
	426	mlen = 0;
	427	} else
	428	mlen = -1;
	429	} else if (mlen == -1)
	430	s_util.c[0] = (char )w;
	431	}
	432	if (len)
	433	printf("cksum: out of data\n");
	434	if (mlen == -1) {
	435	/* The last mbuf has odd # of bytes. Follow the
	436	standard (the odd byte may be shifted left by 8 bits
	437	or not as determined by endian-ness of the machine) */
	438	s_util.c[1] = 0;
	439	sum += s_util.s;
	440	}
	441	REDUCE;
	442	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	443	return (~sum & 0xffff);
	444	}
	445
	446	#endif