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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 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	*
37839358 A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
1c79356b	11	*
37839358 A	12	* This Original Code and all software distributed under the License are
37839358 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
37839358 A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
1c79356b A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/*
	23	* Copyright (c) 1988, 1992, 1993
	24	* The Regents of the University of California. All rights reserved.
	25	*
	26	* Redistribution and use in source and binary forms, with or without
	27	* modification, are permitted provided that the following conditions
	28	* are met:
	29	* 1. Redistributions of source code must retain the above copyright
	30	* notice, this list of conditions and the following disclaimer.
	31	* 2. Redistributions in binary form must reproduce the above copyright
	32	* notice, this list of conditions and the following disclaimer in the
	33	* documentation and/or other materials provided with the distribution.
	34	* 3. All advertising materials mentioning features or use of this software
	35	* must display the following acknowledgement:
	36	* This product includes software developed by the University of
	37	* California, Berkeley and its contributors.
	38	* 4. Neither the name of the University nor the names of its contributors
	39	* may be used to endorse or promote products derived from this software
	40	* without specific prior written permission.
	41	*
	42	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	43	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	44	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	45	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	46	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	47	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	48	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	49	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	50	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	51	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	52	* SUCH DAMAGE.
	53	*
	54	* @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
	55	*/
	56
	57	#include <sys/param.h>
	58	#include <sys/mbuf.h>
	59	#include <sys/kdebug.h>
	60
	61	#define DBG_FNC_IN_CKSUM NETDBG_CODE(DBG_NETIP, (3 << 8))
	62
	63	/*
	64	* Checksum routine for Internet Protocol family headers (Portable Version).
	65	*
	66	* This routine is very heavily used in the network
	67	* code and should be modified for each CPU to be as fast as possible.
	68	*/
	69
0b4e3aa0 A	70	union s_util {
	71	char c[2];
	72	u_short s;
	73	};
1c79356b	74
0b4e3aa0 A	75	union l_util {
	76	u_int16_t s[2];
	77	u_int32_t l;
	78	};
1c79356b	79
0b4e3aa0 A	80	union q_util {
	81	u_int16_t s[4];
	82	u_int32_t l[2];
	83	u_int64_t q;
	84	};
	85
	86	#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
	87
	88	#define REDUCE32 \
	89	{ \
	90	q_util.q = sum; \
	91	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	92	}
	93	#define REDUCE16 \
	94	{ \
	95	q_util.q = sum; \
	96	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	97	sum = l_util.s[0] + l_util.s[1]; \
	98	ADDCARRY(sum); \
	99	}
	100
	101	#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
	102
	103
1c79356b A	104	#if defined(ppc)
1c79356b A	105
0b4e3aa0 A	106	__inline unsigned short
	107	in_addword(u_short a, u_short b)
	108	{
	109	union l_util l_util;
	110	u_int32_t sum = a + b;
	111	REDUCE;
	112	return (sum);
	113	}
	114
	115	__inline unsigned short
	116	in_pseudo(u_int a, u_int b, u_int c)
	117	{
	118	u_int64_t sum;
	119	union q_util q_util;
	120	union l_util l_util;
	121
	122	sum = (u_int64_t) a + b + c;
	123	REDUCE16;
	124	return (sum);
	125
	126	}
	127
1c79356b A	128	int
	129	in_cksum(m, len)
	130	register struct mbuf *m;
	131	register int len;
	132	{
	133	register u_short *w;
	134	register int sum = 0;
	135	register int mlen = 0;
	136	int starting_on_odd = 0;
	137
	138
	139	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	140
	141	for (;m && len; m = m->m_next) {
	142	if (m->m_len == 0)
	143	continue;
	144	mlen = m->m_len;
	145	w = mtod(m, u_short *);
	146
	147	if (len < mlen)
	148	mlen = len;
	149
	150	sum = xsum_assym(w, mlen, sum, starting_on_odd);
	151	len -= mlen;
	152	if (mlen & 0x1)
	153	{
	154	if (starting_on_odd)
	155	starting_on_odd = 0;
	156	else
	157	starting_on_odd = 1;
	158	}
	159	}
	160
	161	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	162	return (~sum & 0xffff);
	163	}
	164
0b4e3aa0 A	165	u_short
	166	in_cksum_skip(m, len, skip)
	167	register struct mbuf *m;
	168	register int len;
	169	register int skip;
	170	{
	171	register u_short *w;
	172	register int sum = 0;
	173	register int mlen = 0;
	174	int starting_on_odd = 0;
	175
	176	len -= skip;
	177	for (; skip && m; m = m->m_next) {
	178	if (m->m_len > skip) {
	179	mlen = m->m_len - skip;
	180	w = (u_short *)(m->m_data+skip);
	181	goto skip_start;
	182	} else {
	183	skip -= m->m_len;
	184	}
	185	}
	186	for (;m && len; m = m->m_next) {
	187	if (m->m_len == 0)
	188	continue;
	189	mlen = m->m_len;
	190	w = mtod(m, u_short *);
	191
765c9de3	192	skip_start:
0b4e3aa0 A	193	if (len < mlen)
0b4e3aa0 A	194	mlen = len;
0b4e3aa0 A	195	sum = xsum_assym(w, mlen, sum, starting_on_odd);
	196	len -= mlen;
	197	if (mlen & 0x1)
	198	{
	199	if (starting_on_odd)
	200	starting_on_odd = 0;
	201	else
	202	starting_on_odd = 1;
	203	}
	204	}
	205
	206	return (~sum & 0xffff);
	207	}
1c79356b A	208	#else
1c79356b A	209
0b4e3aa0 A	210	u_short
	211	in_addword(u_short a, u_short b)
	212	{
	213	union l_util l_util;
	214	u_int32_t sum = a + b;
	215	REDUCE(sum);
	216	return (sum);
	217	}
1c79356b	218
0b4e3aa0 A	219	u_short
	220	in_pseudo(u_int a, u_int b, u_int c)
	221	{
	222	u_int64_t sum;
	223	union q_util q_util;
	224	union l_util l_util;
1c79356b	225
0b4e3aa0 A	226	sum = (u_int64_t) a + b + c;
	227	REDUCE16;
	228	return (sum);
	229	}
1c79356b A	230
	231
	232	int
	233	in_cksum(m, len)
	234	register struct mbuf *m;
	235	register int len;
	236	{
	237	register u_short *w;
	238	register int sum = 0;
	239	register int mlen = 0;
	240	int byte_swapped = 0;
0b4e3aa0 A	241	union s_util s_util;
0b4e3aa0 A	242	union l_util l_util;
1c79356b A	243
	244	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	245
	246	for (;m && len; m = m->m_next) {
	247	if (m->m_len == 0)
	248	continue;
	249	w = mtod(m, u_short *);
	250	if (mlen == -1) {
	251	/*
	252	* The first byte of this mbuf is the continuation
	253	* of a word spanning between this mbuf and the
	254	* last mbuf.
	255	*
	256	* s_util.c[0] is already saved when scanning previous
	257	* mbuf.
	258	*/
	259	s_util.c[1] = (char )w;
	260	sum += s_util.s;
	261	w = (u_short )((char )w + 1);
	262	mlen = m->m_len - 1;
	263	len--;
	264	} else
	265	mlen = m->m_len;
	266	if (len < mlen)
	267	mlen = len;
	268	len -= mlen;
	269	/*
	270	* Force to even boundary.
	271	*/
	272	if ((1 & (int) w) && (mlen > 0)) {
	273	REDUCE;
	274	sum <<= 8;
	275	s_util.c[0] = (u_char )w;
	276	w = (u_short )((char )w + 1);
	277	mlen--;
	278	byte_swapped = 1;
	279	}
	280	/*
	281	* Unroll the loop to make overhead from
	282	* branches &c small.
	283	*/
	284	while ((mlen -= 32) >= 0) {
	285	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	286	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
0b4e3aa0 A	287	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	288	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	289	w += 16;
	290	}
	291	mlen += 32;
	292	while ((mlen -= 8) >= 0) {
	293	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	294	w += 4;
	295	}
	296	mlen += 8;
	297	if (mlen == 0 && byte_swapped == 0)
	298	continue;
	299	REDUCE;
	300	while ((mlen -= 2) >= 0) {
	301	sum += *w++;
	302	}
	303	if (byte_swapped) {
	304	REDUCE;
	305	sum <<= 8;
	306	byte_swapped = 0;
	307	if (mlen == -1) {
	308	s_util.c[1] = (char )w;
	309	sum += s_util.s;
	310	mlen = 0;
	311	} else
	312	mlen = -1;
	313	} else if (mlen == -1)
	314	s_util.c[0] = (char )w;
	315	}
	316	if (len)
	317	printf("cksum: out of data\n");
	318	if (mlen == -1) {
	319	/* The last mbuf has odd # of bytes. Follow the
	320	standard (the odd byte may be shifted left by 8 bits
	321	or not as determined by endian-ness of the machine) */
	322	s_util.c[1] = 0;
	323	sum += s_util.s;
	324	}
	325	REDUCE;
	326	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	327	return (~sum & 0xffff);
	328	}
	329
	330	int
	331	in_cksum_skip(m, len, skip)
	332	register struct mbuf *m;
	333	register u_short len;
	334	register u_short skip;
	335	{
	336	register u_short *w;
	337	register int sum = 0;
	338	register int mlen = 0;
	339	int byte_swapped = 0;
	340	union s_util s_util;
	341	union l_util l_util;
	342
	343	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	344
	345	len -= skip;
	346	for (; skip && m; m = m->m_next) {
	347	if (m->m_len > skip) {
	348	mlen = m->m_len - skip;
	349	w = (u_short *)(m->m_data+skip);
	350	goto skip_start;
351	} else {
352	skip -= m->m_len;
353	}
354	}
355	for (;m && len; m = m->m_next) {
356	if (m->m_len == 0)
357	continue;
358	w = mtod(m, u_short *);
359
360	if (mlen == -1) {
361	/*
362	* The first byte of this mbuf is the continuation
363	* of a word spanning between this mbuf and the
364	* last mbuf.
365	*
366	* s_util.c[0] is already saved when scanning previous
367	* mbuf.
368	*/
369	s_util.c[1] = (char )w;
370	sum += s_util.s;
371	w = (u_short )((char )w + 1);
372	mlen = m->m_len - 1;
373	len--;
374	} else {
375	mlen = m->m_len;
376	}
0b4e3aa0	377	skip_start:
765c9de3 A	378	if (len < mlen)
765c9de3 A	379	mlen = len;
0b4e3aa0 A	380
	381	len -= mlen;
	382	/*
	383	* Force to even boundary.
	384	*/
	385	if ((1 & (int) w) && (mlen > 0)) {
	386	REDUCE;
	387	sum <<= 8;
	388	s_util.c[0] = (u_char )w;
	389	w = (u_short )((char )w + 1);
	390	mlen--;
	391	byte_swapped = 1;
	392	}
	393	/*
	394	* Unroll the loop to make overhead from
	395	* branches &c small.
	396	*/
	397	while ((mlen -= 32) >= 0) {
	398	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	399	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
1c79356b A	400	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	401	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	402	w += 16;
	403	}
	404	mlen += 32;
	405	while ((mlen -= 8) >= 0) {
	406	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	407	w += 4;
	408	}
	409	mlen += 8;
	410	if (mlen == 0 && byte_swapped == 0)
	411	continue;
	412	REDUCE;
	413	while ((mlen -= 2) >= 0) {
	414	sum += *w++;
	415	}
	416	if (byte_swapped) {
	417	REDUCE;
	418	sum <<= 8;
	419	byte_swapped = 0;
	420	if (mlen == -1) {
	421	s_util.c[1] = (char )w;
	422	sum += s_util.s;
	423	mlen = 0;
	424	} else
	425	mlen = -1;
	426	} else if (mlen == -1)
	427	s_util.c[0] = (char )w;
	428	}
	429	if (len)
	430	printf("cksum: out of data\n");
	431	if (mlen == -1) {
	432	/* The last mbuf has odd # of bytes. Follow the
	433	standard (the odd byte may be shifted left by 8 bits
	434	or not as determined by endian-ness of the machine) */
	435	s_util.c[1] = 0;
	436	sum += s_util.s;
	437	}
	438	REDUCE;
	439	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	440	return (~sum & 0xffff);
	441	}
	442
	443	#endif