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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * 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. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * 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_OSREFERENCE_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	1	/*
5d5c5d0d A	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
5d5c5d0d A	3	*
8f6c56a5	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
8f6c56a5 A	6	* This file contains Original Code and/or Modifications of Original Code
	7	* as defined in and that are subject to the Apple Public Source License
	8	* Version 2.0 (the 'License'). You may not use this file except in
	9	* compliance with the License. The rights granted to you under the License
	10	* may not be used to create, or enable the creation or redistribution of,
	11	* unlawful or unlicensed copies of an Apple operating system, or to
	12	* circumvent, violate, or enable the circumvention or violation of, any
	13	* terms of an Apple operating system software license agreement.
	14	*
	15	* Please obtain a copy of the License at
	16	* http://www.opensource.apple.com/apsl/ and read it before using this file.
	17	*
	18	* The Original Code and all software distributed under the License are
	19	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
8ad349bb	24	* limitations under the License.
8f6c56a5 A	25	*
8f6c56a5 A	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	27	*/
	28	/*
	29	* Copyright (c) 1988, 1992, 1993
	30	* The Regents of the University of California. All rights reserved.
	31	*
	32	* Redistribution and use in source and binary forms, with or without
	33	* modification, are permitted provided that the following conditions
	34	* are met:
	35	* 1. Redistributions of source code must retain the above copyright
	36	* notice, this list of conditions and the following disclaimer.
	37	* 2. Redistributions in binary form must reproduce the above copyright
	38	* notice, this list of conditions and the following disclaimer in the
	39	* documentation and/or other materials provided with the distribution.
	40	* 3. All advertising materials mentioning features or use of this software
	41	* must display the following acknowledgement:
	42	* This product includes software developed by the University of
	43	* California, Berkeley and its contributors.
	44	* 4. Neither the name of the University nor the names of its contributors
	45	* may be used to endorse or promote products derived from this software
	46	* without specific prior written permission.
	47	*
	48	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	49	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	50	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	51	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	52	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	53	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	54	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	55	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	56	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	57	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	58	* SUCH DAMAGE.
	59	*
	60	* @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
	61	*/
	62
	63	#include <sys/param.h>
	64	#include <sys/mbuf.h>
	65	#include <sys/kdebug.h>
	66
	67	#define DBG_FNC_IN_CKSUM NETDBG_CODE(DBG_NETIP, (3 << 8))
	68
	69	/*
	70	* Checksum routine for Internet Protocol family headers (Portable Version).
	71	*
	72	* This routine is very heavily used in the network
	73	* code and should be modified for each CPU to be as fast as possible.
	74	*/
	75
0b4e3aa0 A	76	union s_util {
	77	char c[2];
	78	u_short s;
	79	};
1c79356b	80
0b4e3aa0 A	81	union l_util {
	82	u_int16_t s[2];
	83	u_int32_t l;
	84	};
1c79356b	85
0b4e3aa0 A	86	union q_util {
	87	u_int16_t s[4];
	88	u_int32_t l[2];
	89	u_int64_t q;
	90	};
	91
	92	#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
	93
	94	#define REDUCE32 \
	95	{ \
	96	q_util.q = sum; \
	97	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	98	}
	99	#define REDUCE16 \
	100	{ \
	101	q_util.q = sum; \
	102	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	103	sum = l_util.s[0] + l_util.s[1]; \
	104	ADDCARRY(sum); \
	105	}
	106
	107	#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
	108
	109
1c79356b A	110	#if defined(ppc)
1c79356b A	111
0b4e3aa0 A	112	__inline unsigned short
	113	in_addword(u_short a, u_short b)
	114	{
	115	union l_util l_util;
	116	u_int32_t sum = a + b;
	117	REDUCE;
	118	return (sum);
	119	}
	120
	121	__inline unsigned short
	122	in_pseudo(u_int a, u_int b, u_int c)
	123	{
	124	u_int64_t sum;
	125	union q_util q_util;
	126	union l_util l_util;
	127
	128	sum = (u_int64_t) a + b + c;
	129	REDUCE16;
	130	return (sum);
	131
	132	}
	133
1c79356b A	134	int
	135	in_cksum(m, len)
	136	register struct mbuf *m;
	137	register int len;
	138	{
	139	register u_short *w;
	140	register int sum = 0;
	141	register int mlen = 0;
	142	int starting_on_odd = 0;
	143
	144
	145	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	146
	147	for (;m && len; m = m->m_next) {
	148	if (m->m_len == 0)
	149	continue;
	150	mlen = m->m_len;
	151	w = mtod(m, u_short *);
	152
	153	if (len < mlen)
	154	mlen = len;
	155
	156	sum = xsum_assym(w, mlen, sum, starting_on_odd);
	157	len -= mlen;
	158	if (mlen & 0x1)
	159	{
	160	if (starting_on_odd)
	161	starting_on_odd = 0;
	162	else
	163	starting_on_odd = 1;
	164	}
	165	}
	166
	167	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	168	return (~sum & 0xffff);
	169	}
	170
0b4e3aa0 A	171	u_short
	172	in_cksum_skip(m, len, skip)
	173	register struct mbuf *m;
	174	register int len;
	175	register int skip;
	176	{
	177	register u_short *w;
	178	register int sum = 0;
	179	register int mlen = 0;
	180	int starting_on_odd = 0;
	181
	182	len -= skip;
	183	for (; skip && m; m = m->m_next) {
	184	if (m->m_len > skip) {
	185	mlen = m->m_len - skip;
	186	w = (u_short *)(m->m_data+skip);
	187	goto skip_start;
	188	} else {
	189	skip -= m->m_len;
	190	}
	191	}
	192	for (;m && len; m = m->m_next) {
	193	if (m->m_len == 0)
	194	continue;
	195	mlen = m->m_len;
	196	w = mtod(m, u_short *);
	197
765c9de3	198	skip_start:
0b4e3aa0 A	199	if (len < mlen)
0b4e3aa0 A	200	mlen = len;
0b4e3aa0 A	201	sum = xsum_assym(w, mlen, sum, starting_on_odd);
	202	len -= mlen;
	203	if (mlen & 0x1)
	204	{
	205	if (starting_on_odd)
	206	starting_on_odd = 0;
	207	else
	208	starting_on_odd = 1;
	209	}
	210	}
	211
	212	return (~sum & 0xffff);
	213	}
1c79356b A	214	#else
1c79356b A	215
0b4e3aa0 A	216	u_short
	217	in_addword(u_short a, u_short b)
	218	{
	219	union l_util l_util;
	220	u_int32_t sum = a + b;
	221	REDUCE(sum);
	222	return (sum);
	223	}
1c79356b	224
0b4e3aa0 A	225	u_short
	226	in_pseudo(u_int a, u_int b, u_int c)
	227	{
	228	u_int64_t sum;
	229	union q_util q_util;
	230	union l_util l_util;
1c79356b	231
0b4e3aa0 A	232	sum = (u_int64_t) a + b + c;
	233	REDUCE16;
	234	return (sum);
	235	}
1c79356b A	236
	237
	238	int
	239	in_cksum(m, len)
	240	register struct mbuf *m;
	241	register int len;
	242	{
	243	register u_short *w;
	244	register int sum = 0;
	245	register int mlen = 0;
	246	int byte_swapped = 0;
0b4e3aa0 A	247	union s_util s_util;
0b4e3aa0 A	248	union l_util l_util;
1c79356b A	249
	250	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	251
	252	for (;m && len; m = m->m_next) {
	253	if (m->m_len == 0)
	254	continue;
	255	w = mtod(m, u_short *);
	256	if (mlen == -1) {
	257	/*
	258	* The first byte of this mbuf is the continuation
	259	* of a word spanning between this mbuf and the
	260	* last mbuf.
	261	*
	262	* s_util.c[0] is already saved when scanning previous
	263	* mbuf.
	264	*/
	265	s_util.c[1] = (char )w;
	266	sum += s_util.s;
	267	w = (u_short )((char )w + 1);
	268	mlen = m->m_len - 1;
	269	len--;
	270	} else
	271	mlen = m->m_len;
	272	if (len < mlen)
	273	mlen = len;
	274	len -= mlen;
	275	/*
	276	* Force to even boundary.
	277	*/
	278	if ((1 & (int) w) && (mlen > 0)) {
	279	REDUCE;
	280	sum <<= 8;
	281	s_util.c[0] = (u_char )w;
	282	w = (u_short )((char )w + 1);
	283	mlen--;
	284	byte_swapped = 1;
	285	}
	286	/*
	287	* Unroll the loop to make overhead from
	288	* branches &c small.
	289	*/
	290	while ((mlen -= 32) >= 0) {
	291	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	292	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
0b4e3aa0 A	293	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	294	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	295	w += 16;
	296	}
	297	mlen += 32;
	298	while ((mlen -= 8) >= 0) {
	299	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	300	w += 4;
	301	}
	302	mlen += 8;
	303	if (mlen == 0 && byte_swapped == 0)
	304	continue;
	305	REDUCE;
	306	while ((mlen -= 2) >= 0) {
	307	sum += *w++;
	308	}
	309	if (byte_swapped) {
	310	REDUCE;
	311	sum <<= 8;
	312	byte_swapped = 0;
	313	if (mlen == -1) {
	314	s_util.c[1] = (char )w;
	315	sum += s_util.s;
	316	mlen = 0;
	317	} else
	318	mlen = -1;
	319	} else if (mlen == -1)
	320	s_util.c[0] = (char )w;
	321	}
	322	if (len)
	323	printf("cksum: out of data\n");
	324	if (mlen == -1) {
	325	/* The last mbuf has odd # of bytes. Follow the
	326	standard (the odd byte may be shifted left by 8 bits
	327	or not as determined by endian-ness of the machine) */
	328	s_util.c[1] = 0;
	329	sum += s_util.s;
	330	}
	331	REDUCE;
	332	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	333	return (~sum & 0xffff);
	334	}
	335
	336	int
	337	in_cksum_skip(m, len, skip)
	338	register struct mbuf *m;
	339	register u_short len;
	340	register u_short skip;
	341	{
	342	register u_short *w;
	343	register int sum = 0;
	344	register int mlen = 0;
	345	int byte_swapped = 0;
	346	union s_util s_util;
	347	union l_util l_util;
	348
	349	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	350
	351	len -= skip;
	352	for (; skip && m; m = m->m_next) {
	353	if (m->m_len > skip) {
	354	mlen = m->m_len - skip;
	355	w = (u_short *)(m->m_data+skip);
	356	goto skip_start;
357	} else {
358	skip -= m->m_len;
359	}
360	}
361	for (;m && len; m = m->m_next) {
362	if (m->m_len == 0)
363	continue;
364	w = mtod(m, u_short *);
365
366	if (mlen == -1) {
367	/*
368	* The first byte of this mbuf is the continuation
369	* of a word spanning between this mbuf and the
370	* last mbuf.
371	*
372	* s_util.c[0] is already saved when scanning previous
373	* mbuf.
374	*/
375	s_util.c[1] = (char )w;
376	sum += s_util.s;
377	w = (u_short )((char )w + 1);
378	mlen = m->m_len - 1;
379	len--;
380	} else {
381	mlen = m->m_len;
382	}
0b4e3aa0	383	skip_start:
765c9de3 A	384	if (len < mlen)
765c9de3 A	385	mlen = len;
0b4e3aa0 A	386
	387	len -= mlen;
	388	/*
	389	* Force to even boundary.
	390	*/
	391	if ((1 & (int) w) && (mlen > 0)) {
	392	REDUCE;
	393	sum <<= 8;
	394	s_util.c[0] = (u_char )w;
	395	w = (u_short )((char )w + 1);
	396	mlen--;
	397	byte_swapped = 1;
	398	}
	399	/*
	400	* Unroll the loop to make overhead from
	401	* branches &c small.
	402	*/
	403	while ((mlen -= 32) >= 0) {
	404	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	405	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
1c79356b A	406	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	407	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	408	w += 16;
	409	}
	410	mlen += 32;
	411	while ((mlen -= 8) >= 0) {
	412	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	413	w += 4;
	414	}
	415	mlen += 8;
	416	if (mlen == 0 && byte_swapped == 0)
	417	continue;
	418	REDUCE;
	419	while ((mlen -= 2) >= 0) {
	420	sum += *w++;
	421	}
	422	if (byte_swapped) {
	423	REDUCE;
	424	sum <<= 8;
	425	byte_swapped = 0;
	426	if (mlen == -1) {
	427	s_util.c[1] = (char )w;
	428	sum += s_util.s;
	429	mlen = 0;
	430	} else
	431	mlen = -1;
	432	} else if (mlen == -1)
	433	s_util.c[0] = (char )w;
	434	}
	435	if (len)
	436	printf("cksum: out of data\n");
	437	if (mlen == -1) {
	438	/* The last mbuf has odd # of bytes. Follow the
	439	standard (the odd byte may be shifted left by 8 bits
	440	or not as determined by endian-ness of the machine) */
	441	s_util.c[1] = 0;
	442	sum += s_util.s;
	443	}
	444	REDUCE;
	445	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	446	return (~sum & 0xffff);
	447	}
	448
	449	#endif