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

/*
 * Copyright (c) 2000-2009 Apple 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>
#include <kern/debug.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <libkern/libkern.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);}

u_int16_t inet_cksum_simple(struct mbuf *, int);

u_int16_t
inet_cksum_simple(struct mbuf *m, int len)
{
	return (inet_cksum(m, 0, 0, len));
}

inline u_short
in_addword(u_short a, u_short b)
{
        union l_util l_util;
	u_int32_t sum = a + b;

	REDUCE;
	return (sum);
}

inline 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);

}

#if defined(__ppc__)

extern u_short xsum_assym(u_short *p, int len, u_short xsum, int odd);

u_int16_t
inet_cksum(struct mbuf *m, unsigned int nxt, unsigned int skip,
    unsigned int len)
{
	u_short *w;
	u_int32_t sum = 0;
	int mlen = 0;
	int starting_on_odd  = 0;

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

	/* sanity check */
	if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < skip + len) {
		panic("inet_cksum: mbuf len (%d) < off+len (%d+%d)\n",
		    m->m_pkthdr.len, skip, len);
	}

	/* include pseudo header checksum? */
	if (nxt != 0) {
		struct ip *iph;

		if (m->m_len < sizeof (struct ip))
			panic("inet_cksum: bad mbuf chain");

		iph = mtod(m, struct ip *);
		sum = in_pseudo(iph->ip_src.s_addr, iph->ip_dst.s_addr,
		    htonl(len + nxt));
	}

	if (skip != 0) {
		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;
		}
	}

	KERNEL_DEBUG(DBG_FNC_IN_CKSUM | DBG_FUNC_END, 0,0,0,0,0);

	return (~sum & 0xffff);
}

#elif defined(__arm__) && __ARM_ARCH__ >= 6

extern int cpu_in_cksum(struct mbuf *m, int len, int off, uint32_t initial_sum);

u_int16_t
inet_cksum(struct mbuf *m, unsigned int nxt, unsigned int skip,
    unsigned int len)
{
	u_int32_t sum = 0;

	/* sanity check */
	if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < skip + len) {
		panic("inet_cksum: mbuf len (%d) < off+len (%d+%d)\n",
		    m->m_pkthdr.len, skip, len);
	}

	/* include pseudo header checksum? */
	if (nxt != 0) {
		struct ip *iph;

		if (m->m_len < sizeof (struct ip))
			panic("inet_cksum: bad mbuf chain");

		iph = mtod(m, struct ip *);
		sum = in_pseudo(iph->ip_src.s_addr, iph->ip_dst.s_addr,
		    htonl(len + nxt));
	}

	return (cpu_in_cksum(m, len, skip, sum));
}

#else

u_int16_t
inet_cksum(struct mbuf *m, unsigned int nxt, unsigned int skip,
    unsigned int len)
{
	u_short *w;
	u_int32_t sum = 0;
	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);

	/* sanity check */
	if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < skip + len) {
		panic("inet_cksum: mbuf len (%d) < off+len (%d+%d)\n",
		    m->m_pkthdr.len, skip, len);
	}

	/* include pseudo header checksum? */
	if (nxt != 0) {
		struct ip *iph;

		if (m->m_len < sizeof (struct ip))
			panic("inet_cksum: bad mbuf chain");

		iph = mtod(m, struct ip *);
		sum = in_pseudo(iph->ip_src.s_addr, iph->ip_dst.s_addr,
		    htonl(len + nxt));
	}

	if (skip != 0) {
		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 & (uintptr_t) 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 by %d\n", len);
	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	/*
b0d623f7	2	* Copyright (c) 2000-2009 Apple Inc. All rights reserved.
5d5c5d0d	3	*
2d21ac55	4	* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
1c79356b	5	*
2d21ac55 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.
8f6c56a5	14	*
2d21ac55 A	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
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	22	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	23	* Please see the License for the specific language governing rights and
	24	* limitations under the License.
8f6c56a5	25	*
2d21ac55	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>
2d21ac55 A	66	#include <kern/debug.h>
	67	#include <netinet/in.h>
	68	#include <netinet/ip.h>
b0d623f7	69	#include <libkern/libkern.h>
1c79356b A	70
	71	#define DBG_FNC_IN_CKSUM NETDBG_CODE(DBG_NETIP, (3 << 8))
	72
	73	/*
	74	* Checksum routine for Internet Protocol family headers (Portable Version).
	75	*
	76	* This routine is very heavily used in the network
	77	* code and should be modified for each CPU to be as fast as possible.
	78	*/
	79
0b4e3aa0 A	80	union s_util {
	81	char c[2];
	82	u_short s;
	83	};
1c79356b	84
0b4e3aa0 A	85	union l_util {
0b4e3aa0 A	86	u_int16_t s[2];
2d21ac55	87	u_int32_t l;
0b4e3aa0	88	};
1c79356b	89
0b4e3aa0 A	90	union q_util {
	91	u_int16_t s[4];
	92	u_int32_t l[2];
	93	u_int64_t q;
2d21ac55	94	};
0b4e3aa0 A	95
	96	#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
	97
	98	#define REDUCE32 \
	99	{ \
	100	q_util.q = sum; \
	101	sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	102	}
	103	#define REDUCE16 \
	104	{ \
	105	q_util.q = sum; \
	106	l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
	107	sum = l_util.s[0] + l_util.s[1]; \
	108	ADDCARRY(sum); \
	109	}
	110
	111	#define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; ADDCARRY(sum);}
	112
2d21ac55 A	113	u_int16_t inet_cksum_simple(struct mbuf *, int);
	114
	115	u_int16_t
	116	inet_cksum_simple(struct mbuf *m, int len)
	117	{
	118	return (inet_cksum(m, 0, 0, len));
	119	}
1c79356b	120
2d21ac55	121	inline u_short
0b4e3aa0 A	122	in_addword(u_short a, u_short b)
0b4e3aa0 A	123	{
2d21ac55	124	union l_util l_util;
0b4e3aa0	125	u_int32_t sum = a + b;
2d21ac55	126
0b4e3aa0 A	127	REDUCE;
	128	return (sum);
	129	}
	130
2d21ac55	131	inline u_short
0b4e3aa0 A	132	in_pseudo(u_int a, u_int b, u_int c)
	133	{
	134	u_int64_t sum;
	135	union q_util q_util;
2d21ac55	136	union l_util l_util;
0b4e3aa0 A	137
	138	sum = (u_int64_t) a + b + c;
	139	REDUCE16;
	140	return (sum);
	141
	142	}
	143
b0d623f7 A	144	#if defined(__ppc__)
	145
	146	extern u_short xsum_assym(u_short *p, int len, u_short xsum, int odd);
	147
2d21ac55 A	148	u_int16_t
	149	inet_cksum(struct mbuf *m, unsigned int nxt, unsigned int skip,
	150	unsigned int len)
1c79356b	151	{
2d21ac55 A	152	u_short *w;
	153	u_int32_t sum = 0;
	154	int mlen = 0;
1c79356b A	155	int starting_on_odd = 0;
1c79356b A	156
1c79356b A	157	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
1c79356b A	158
2d21ac55	159	/* sanity check */
593a1d5f	160	if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < skip + len) {
2d21ac55 A	161	panic("inet_cksum: mbuf len (%d) < off+len (%d+%d)\n",
	162	m->m_pkthdr.len, skip, len);
	163	}
1c79356b	164
2d21ac55 A	165	/* include pseudo header checksum? */
	166	if (nxt != 0) {
	167	struct ip *iph;
1c79356b	168
2d21ac55 A	169	if (m->m_len < sizeof (struct ip))
2d21ac55 A	170	panic("inet_cksum: bad mbuf chain");
1c79356b	171
2d21ac55 A	172	iph = mtod(m, struct ip *);
	173	sum = in_pseudo(iph->ip_src.s_addr, iph->ip_dst.s_addr,
	174	htonl(len + nxt));
	175	}
1c79356b	176
2d21ac55 A	177	if (skip != 0) {
	178	for (; skip && m; m = m->m_next) {
	179	if (m->m_len > skip) {
	180	mlen = m->m_len - skip;
	181	w = (u_short *)(m->m_data+skip);
	182	goto skip_start;
	183	} else {
	184	skip -= m->m_len;
	185	}
	186	}
	187	}
0b4e3aa0	188
0b4e3aa0 A	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
2d21ac55 A	209	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
2d21ac55 A	210
0b4e3aa0 A	211	return (~sum & 0xffff);
0b4e3aa0 A	212	}
2d21ac55	213
b0d623f7	214	#elif defined(__arm__) && __ARM_ARCH__ >= 6
1c79356b	215
b0d623f7 A	216	extern int cpu_in_cksum(struct mbuf *m, int len, int off, uint32_t initial_sum);
	217
	218	u_int16_t
	219	inet_cksum(struct mbuf *m, unsigned int nxt, unsigned int skip,
	220	unsigned int len)
2d21ac55	221	{
b0d623f7	222	u_int32_t sum = 0;
2d21ac55	223
b0d623f7 A	224	/* sanity check */
	225	if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < skip + len) {
	226	panic("inet_cksum: mbuf len (%d) < off+len (%d+%d)\n",
	227	m->m_pkthdr.len, skip, len);
	228	}
1c79356b	229
b0d623f7 A	230	/* include pseudo header checksum? */
	231	if (nxt != 0) {
	232	struct ip *iph;
1c79356b	233
b0d623f7 A	234	if (m->m_len < sizeof (struct ip))
	235	panic("inet_cksum: bad mbuf chain");
	236
	237	iph = mtod(m, struct ip *);
	238	sum = in_pseudo(iph->ip_src.s_addr, iph->ip_dst.s_addr,
	239	htonl(len + nxt));
	240	}
	241
	242	return (cpu_in_cksum(m, len, skip, sum));
0b4e3aa0	243	}
1c79356b	244
b0d623f7 A	245	#else
b0d623f7 A	246
2d21ac55 A	247	u_int16_t
	248	inet_cksum(struct mbuf *m, unsigned int nxt, unsigned int skip,
	249	unsigned int len)
1c79356b	250	{
2d21ac55 A	251	u_short *w;
	252	u_int32_t sum = 0;
	253	int mlen = 0;
1c79356b	254	int byte_swapped = 0;
0b4e3aa0	255	union s_util s_util;
2d21ac55	256	union l_util l_util;
1c79356b A	257
	258	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_START, len,0,0,0,0);
	259
2d21ac55	260	/* sanity check */
593a1d5f	261	if ((m->m_flags & M_PKTHDR) && m->m_pkthdr.len < skip + len) {
2d21ac55 A	262	panic("inet_cksum: mbuf len (%d) < off+len (%d+%d)\n",
2d21ac55 A	263	m->m_pkthdr.len, skip, len);
0b4e3aa0	264	}
0b4e3aa0	265
2d21ac55 A	266	/* include pseudo header checksum? */
	267	if (nxt != 0) {
	268	struct ip *iph;
0b4e3aa0	269
2d21ac55 A	270	if (m->m_len < sizeof (struct ip))
	271	panic("inet_cksum: bad mbuf chain");
	272
	273	iph = mtod(m, struct ip *);
	274	sum = in_pseudo(iph->ip_src.s_addr, iph->ip_dst.s_addr,
	275	htonl(len + nxt));
	276	}
0b4e3aa0	277
2d21ac55 A	278	if (skip != 0) {
	279	for (; skip && m; m = m->m_next) {
	280	if (m->m_len > skip) {
	281	mlen = m->m_len - skip;
	282	w = (u_short *)(m->m_data+skip);
	283	goto skip_start;
	284	} else {
	285	skip -= m->m_len;
	286	}
	287	}
	288	}
0b4e3aa0 A	289	for (;m && len; m = m->m_next) {
	290	if (m->m_len == 0)
	291	continue;
	292	w = mtod(m, u_short *);
	293
	294	if (mlen == -1) {
	295	/*
	296	* The first byte of this mbuf is the continuation
	297	* of a word spanning between this mbuf and the
	298	* last mbuf.
	299	*
	300	* s_util.c[0] is already saved when scanning previous
	301	* mbuf.
	302	*/
	303	s_util.c[1] = (char )w;
	304	sum += s_util.s;
	305	w = (u_short )((char )w + 1);
	306	mlen = m->m_len - 1;
	307	len--;
	308	} else {
2d21ac55	309	mlen = m->m_len;
0b4e3aa0	310	}
0b4e3aa0	311	skip_start:
765c9de3	312	if (len < mlen)
2d21ac55	313	mlen = len;
0b4e3aa0 A	314
	315	len -= mlen;
	316	/*
	317	* Force to even boundary.
	318	*/
b0d623f7	319	if ((1 & (uintptr_t) w) && (mlen > 0)) {
0b4e3aa0 A	320	REDUCE;
	321	sum <<= 8;
	322	s_util.c[0] = (u_char )w;
	323	w = (u_short )((char )w + 1);
	324	mlen--;
	325	byte_swapped = 1;
	326	}
	327	/*
	328	* Unroll the loop to make overhead from
	329	* branches &c small.
	330	*/
	331	while ((mlen -= 32) >= 0) {
	332	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	333	sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
1c79356b A	334	sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
	335	sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
	336	w += 16;
	337	}
	338	mlen += 32;
	339	while ((mlen -= 8) >= 0) {
	340	sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
	341	w += 4;
	342	}
	343	mlen += 8;
	344	if (mlen == 0 && byte_swapped == 0)
	345	continue;
	346	REDUCE;
	347	while ((mlen -= 2) >= 0) {
	348	sum += *w++;
	349	}
	350	if (byte_swapped) {
	351	REDUCE;
	352	sum <<= 8;
	353	byte_swapped = 0;
	354	if (mlen == -1) {
	355	s_util.c[1] = (char )w;
	356	sum += s_util.s;
	357	mlen = 0;
	358	} else
	359	mlen = -1;
	360	} else if (mlen == -1)
	361	s_util.c[0] = (char )w;
	362	}
	363	if (len)
2d21ac55	364	printf("cksum: out of data by %d\n", len);
1c79356b A	365	if (mlen == -1) {
	366	/* The last mbuf has odd # of bytes. Follow the
	367	standard (the odd byte may be shifted left by 8 bits
	368	or not as determined by endian-ness of the machine) */
	369	s_util.c[1] = 0;
	370	sum += s_util.s;
	371	}
	372	REDUCE;
	373	KERNEL_DEBUG(DBG_FNC_IN_CKSUM \| DBG_FUNC_END, 0,0,0,0,0);
	374	return (~sum & 0xffff);
	375	}
	376
	377	#endif