[unix-history] / usr / src / sys / netiso / iso_chksum.c

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)iso_chksum.c	7.9 (Berkeley) %G%
 */

/***********************************************************
		Copyright IBM Corporation 1987

                      All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of IBM not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/

/*
 * ARGO Project, Computer Sciences Dept., University of Wisconsin - Madison
 */
/* 
 * $Header: iso_chksum.c,v 4.7 88/07/29 15:31:26 nhall Exp $
 * $Source: /usr/argo/sys/netiso/RCS/iso_chksum.c,v $
 *
 * ISO CHECKSUM
 *
 * The checksum generation and check routines are here.
 * The checksum is 2 bytes such that the sum of all the bytes b(i) == 0
 * and the sum of i * b(i) == 0.
 * The whole thing is complicated by the fact that the data are in mbuf
 * chains.
 * Furthermore, there is the possibility of wraparound in the running
 * sums after adding up 4102 octets.  In order to avoid doing a mod
 * operation after EACH add, we have restricted this implementation to 
 * negotiating a maximum of 4096-octets per TPDU (for the transport layer).
 * The routine iso_check_csum doesn't need to know where the checksum
 * octets are.
 * The routine iso_gen_csum takes a pointer to an mbuf chain (logically
 * a chunk of data), an offset into the chunk at which the 2 octets are to
 * be stuffed, and the length of the chunk.  The 2 octets have to be
 * logically adjacent, but may be physically located in separate mbufs.
 */

#ifdef ISO
#include <netiso/argo_debug.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#endif /* ISO */

#ifndef MNULL
#define MNULL (struct mbuf *)0
#endif /* MNULL */

/*
 * FUNCTION:	iso_check_csum
 *
 * PURPOSE:		To check the checksum of the packet in the mbuf chain (m).
 * 				The total length of the packet is (len).
 * 				Called from tp_input() and clnp_intr()
 *
 * RETURNS:		 TRUE (something non-zero) if there is a checksum error,
 * 			 	 FALSE if there was NO checksum error.
 *
 * SIDE EFFECTS:  none
 *
 * NOTES:		 It might be possible to gain something by optimizing
 *               this routine (unrolling loops, etc). But it is such
 *				 a horrible thing to fiddle with anyway, it probably
 *				 isn't worth it.
 */
int 
iso_check_csum(m, len)
	struct mbuf *m;
	int len;
{
	register u_char *p = mtod(m, u_char *);
	register u_long c0=0, c1=0;
	register int i=0;
	int cum = 0; /* cumulative length */
	int l;

	l = len;
	len = min(m->m_len, len);
	i = 0;

	IFDEBUG(D_CHKSUM)
		printf("iso_check_csum: m x%x, l x%x, m->m_len x%x\n", m, l, m->m_len);
	ENDDEBUG

	while( i<l ) {
		cum += len;
		while (i<cum) {
			c0 = c0 + *(p++);
			c1 += c0;
			i++;
		}
		if(i < l) {
			m = m->m_next;
			IFDEBUG(D_CHKSUM)
				printf("iso_check_csum: new mbuf\n");
				if(l-i < m->m_len)
					printf(
					"bad mbuf chain in check csum l 0x%x i 0x%x m_data 0x%x",
						l,i,m->m_data);
			ENDDEBUG
			ASSERT( m != MNULL);
			len = min( m->m_len, l-i);
			p = mtod(m, u_char *);
		}
	}
	if ( ((int)c0 % 255) || ((int)c1 % 255) ) {
		IFDEBUG(D_CHKSUM)
			printf("BAD iso_check_csum l 0x%x cum 0x%x len 0x%x, i 0x%x", 
				l, cum, len, i);
		ENDDEBUG
		return ((int)c0 % 255)<<8 | ((int)c1 % 255);
	}
	return 0;
}

/*
 * FUNCTION:	iso_gen_csum
 *
 * PURPOSE:		To generate the checksum of the packet in the mbuf chain (m).
 * 				The first of the 2 (logically) adjacent checksum bytes 
 *				(x and y) go at offset (n).
 * 				(n) is an offset relative to the beginning of the data, 
 *				not the beginning of the mbuf.
 * 				(l) is the length of the total mbuf chain's data.
 * 				Called from tp_emit(), tp_error_emit()
 *				clnp_emit_er(), clnp_forward(), clnp_output().
 *
 * RETURNS:		Rien
 *
 * SIDE EFFECTS: Puts the 2 checksum bytes into the packet.
 *
 * NOTES:		Ditto the note for iso_check_csum().
 */

void
iso_gen_csum(m,n,l)
	struct mbuf *m;
	int n; /* offset of 2 checksum bytes */
	int l;
{
	register u_char *p = mtod(m, u_char *);
	register int c0=0, c1=0;
	register int i=0;
	int loc = n++, len=0; /* n is position, loc is offset */
	u_char *xloc;
	u_char *yloc;
	int cum=0;	/* cum == cumulative length */

	IFDEBUG(D_CHKSUM)
		printf("enter gen csum m 0x%x n 0x%x l 0x%x\n",m, n-1 ,l );
	ENDDEBUG

	while(i < l) {
		len = min(m->m_len, CLBYTES);
		/* RAH: don't cksum more than l bytes */
		len = min(len, l - i);

		cum +=len;
		p = mtod(m, u_char *);

		if(loc>=0) {
			if (loc < len) {
				xloc = loc + mtod(m, u_char *);
				IFDEBUG(D_CHKSUM)
					printf("1: zeroing xloc 0x%x loc 0x%x\n",xloc, loc );
				ENDDEBUG
				*xloc = (u_char)0;
				if (loc+1 < len) {
					/* both xloc and yloc are in same mbuf */
					yloc = 1  + xloc;
					IFDEBUG(D_CHKSUM)
						printf("2: zeroing yloc 0x%x loc 0x%x\n",yloc, loc );
					ENDDEBUG
					*yloc = (u_char)0;
				} else {
					/* crosses boundary of mbufs */
					yloc = mtod(m->m_next, u_char *);
					IFDEBUG(D_CHKSUM)
						printf("3: zeroing yloc 0x%x \n",yloc );
					ENDDEBUG
					*yloc = (u_char)0;
				}
			}
			loc -= len;
		}

		while(i < cum) {
			c0 = (c0 + *p);
			c1 += c0 ;
			i++; 
			p++;
		}
		m = m->m_next;
	}
	IFDEBUG(D_CHKSUM)
		printf("gen csum final xloc 0x%x yloc 0x%x\n",xloc, yloc );
	ENDDEBUG

	c1 = (((c0 * (l-n))-c1)%255) ;
	*xloc = (u_char) ((c1 < 0)? c1+255 : c1);

	c1 = (-(int)(c1+c0))%255;
	*yloc = (u_char) (c1 < 0? c1 + 255 : c1);

	IFDEBUG(D_CHKSUM)
		printf("gen csum end \n");
	ENDDEBUG
}

/*
 * FUNCTION:	m_datalen
 *
 * PURPOSE:		returns length of the mbuf chain.
 * 				used all over the iso code.
 *
 * RETURNS:		integer
 *
 * SIDE EFFECTS: none
 *
 * NOTES:		
 */

int
m_datalen (m)
	register struct mbuf *m;
{ 	
	register int datalen;

	for (datalen = 0; m; m = m->m_next)
		datalen += m->m_len;
	return datalen;
}

int
m_compress(in, out)
	register struct mbuf *in, **out;
{
	register 	int datalen = 0;
	int	s = splimp();

	if( in->m_next == MNULL ) {
		*out = in;
		IFDEBUG(D_REQUEST)
			printf("m_compress returning 0x%x: A\n", in->m_len);
		ENDDEBUG
		splx(s);
		return in->m_len;
	}
	MGET((*out), M_DONTWAIT, MT_DATA);
	if((*out) == MNULL) {
		*out = in;
		IFDEBUG(D_REQUEST)
			printf("m_compress returning -1: B\n");
		ENDDEBUG
		splx(s);
		return -1; 
	}
	(*out)->m_len = 0;
	(*out)->m_act = MNULL;

	while (in) {
		IFDEBUG(D_REQUEST)
			printf("m_compress in 0x%x *out 0x%x\n", in, *out);
			printf("m_compress in: len 0x%x, off 0x%x\n", in->m_len, in->m_data);
			printf("m_compress *out: len 0x%x, off 0x%x\n", (*out)->m_len, 
				(*out)->m_data);
		ENDDEBUG
		if (in->m_flags & M_EXT) {
			ASSERT(in->m_len == 0);
		}
		if ( in->m_len == 0) {
			in = in->m_next;
			continue;
		}
		if (((*out)->m_flags & M_EXT) == 0) {
			int len;

			len = M_TRAILINGSPACE(*out);
			len = min(len, in->m_len);
			datalen += len;

			IFDEBUG(D_REQUEST)
				printf("m_compress copying len %d\n", len);
			ENDDEBUG
			bcopy(mtod(in, caddr_t), mtod((*out), caddr_t) + (*out)->m_len,
						(unsigned)len);

			(*out)->m_len += len;
			in->m_len -= len;
			continue;
		} else {
			/* (*out) is full */
			if(( (*out)->m_next = m_get(M_DONTWAIT, MT_DATA) ) == MNULL) {
				m_freem(*out);
				*out = in;
				IFDEBUG(D_REQUEST)
					printf("m_compress returning -1: B\n");
				ENDDEBUG
				splx(s);
				return -1;
			}
			(*out)->m_len = 0;
			(*out)->m_act = MNULL;
			*out = (*out)->m_next;
		}
	}
	m_freem(in);
	IFDEBUG(D_REQUEST)
		printf("m_compress returning 0x%x: A\n", datalen);
	ENDDEBUG
	splx(s);
	return datalen;
}
Commit	Line	Data
7bcd1bb8 KB	1	/*-
	2	* Copyright (c) 1991 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* %sccs.include.redist.c%
	6	*
4d8170e5	7	* @(#)iso_chksum.c 7.9 (Berkeley) %G%
7bcd1bb8 KB	8	*/
7bcd1bb8 KB	9
ee8eb34a KS	10	/***********************************************************
	11	Copyright IBM Corporation 1987
	12
	13	All Rights Reserved
	14
	15	Permission to use, copy, modify, and distribute this software and its
	16	documentation for any purpose and without fee is hereby granted,
	17	provided that the above copyright notice appear in all copies and that
	18	both that copyright notice and this permission notice appear in
	19	supporting documentation, and that the name of IBM not be
	20	used in advertising or publicity pertaining to distribution of the
	21	software without specific, written prior permission.
	22
	23	IBM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
	24	ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
	25	IBM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
	26	ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	27	WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
	28	ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	29	SOFTWARE.
	30
	31	******************************************************************/
	32
	33	/*
	34	* ARGO Project, Computer Sciences Dept., University of Wisconsin - Madison
	35	*/
	36	/*
	37	* $Header: iso_chksum.c,v 4.7 88/07/29 15:31:26 nhall Exp $
	38	* $Source: /usr/argo/sys/netiso/RCS/iso_chksum.c,v $
	39	*
	40	* ISO CHECKSUM
	41	*
	42	* The checksum generation and check routines are here.
	43	* The checksum is 2 bytes such that the sum of all the bytes b(i) == 0
	44	* and the sum of i * b(i) == 0.
	45	* The whole thing is complicated by the fact that the data are in mbuf
	46	* chains.
	47	* Furthermore, there is the possibility of wraparound in the running
	48	* sums after adding up 4102 octets. In order to avoid doing a mod
	49	* operation after EACH add, we have restricted this implementation to
	50	* negotiating a maximum of 4096-octets per TPDU (for the transport layer).
	51	* The routine iso_check_csum doesn't need to know where the checksum
	52	* octets are.
	53	* The routine iso_gen_csum takes a pointer to an mbuf chain (logically
	54	* a chunk of data), an offset into the chunk at which the 2 octets are to
	55	* be stuffed, and the length of the chunk. The 2 octets have to be
	56	* logically adjacent, but may be physically located in separate mbufs.
	57	*/
	58
a50e2bc0	59	#ifdef ISO
5548a02f KB	60	#include <netiso/argo_debug.h>
	61	#include <sys/param.h>
	62	#include <sys/systm.h>
	63	#include <sys/mbuf.h>
4d8170e5	64	#endif /* ISO */
ee8eb34a KS	65
	66	#ifndef MNULL
	67	#define MNULL (struct mbuf *)0
4d8170e5	68	#endif /* MNULL */
ee8eb34a KS	69
	70	/*
	71	* FUNCTION: iso_check_csum
	72	*
	73	* PURPOSE: To check the checksum of the packet in the mbuf chain (m).
	74	* The total length of the packet is (len).
	75	* Called from tp_input() and clnp_intr()
	76	*
	77	* RETURNS: TRUE (something non-zero) if there is a checksum error,
	78	* FALSE if there was NO checksum error.
	79	*
	80	* SIDE EFFECTS: none
	81	*
	82	* NOTES: It might be possible to gain something by optimizing
	83	* this routine (unrolling loops, etc). But it is such
	84	* a horrible thing to fiddle with anyway, it probably
	85	* isn't worth it.
	86	*/
	87	int
	88	iso_check_csum(m, len)
	89	struct mbuf *m;
	90	int len;
	91	{
	92	register u_char p = mtod(m, u_char );
	93	register u_long c0=0, c1=0;
	94	register int i=0;
	95	int cum = 0; /* cumulative length */
	96	int l;
	97
	98	l = len;
8f8c8741	99	len = min(m->m_len, len);
ee8eb34a KS	100	i = 0;
	101
	102	IFDEBUG(D_CHKSUM)
	103	printf("iso_check_csum: m x%x, l x%x, m->m_len x%x\n", m, l, m->m_len);
	104	ENDDEBUG
	105
	106	while( i<l ) {
	107	cum += len;
	108	while (i<cum) {
	109	c0 = c0 + *(p++);
	110	c1 += c0;
	111	i++;
	112	}
	113	if(i < l) {
	114	m = m->m_next;
	115	IFDEBUG(D_CHKSUM)
	116	printf("iso_check_csum: new mbuf\n");
	117	if(l-i < m->m_len)
	118	printf(
a50e2bc0 KS	119	"bad mbuf chain in check csum l 0x%x i 0x%x m_data 0x%x",
a50e2bc0 KS	120	l,i,m->m_data);
ee8eb34a KS	121	ENDDEBUG
ee8eb34a KS	122	ASSERT( m != MNULL);
8f8c8741	123	len = min( m->m_len, l-i);
ee8eb34a KS	124	p = mtod(m, u_char *);
	125	}
	126	}
	127	if ( ((int)c0 % 255) \|\| ((int)c1 % 255) ) {
	128	IFDEBUG(D_CHKSUM)
	129	printf("BAD iso_check_csum l 0x%x cum 0x%x len 0x%x, i 0x%x",
	130	l, cum, len, i);
	131	ENDDEBUG
	132	return ((int)c0 % 255)<<8 \| ((int)c1 % 255);
	133	}
	134	return 0;
	135	}
	136
	137	/*
	138	* FUNCTION: iso_gen_csum
	139	*
	140	* PURPOSE: To generate the checksum of the packet in the mbuf chain (m).
	141	* The first of the 2 (logically) adjacent checksum bytes
	142	* (x and y) go at offset (n).
	143	* (n) is an offset relative to the beginning of the data,
	144	* not the beginning of the mbuf.
	145	* (l) is the length of the total mbuf chain's data.
	146	* Called from tp_emit(), tp_error_emit()
	147	* clnp_emit_er(), clnp_forward(), clnp_output().
	148	*
	149	* RETURNS: Rien
	150	*
	151	* SIDE EFFECTS: Puts the 2 checksum bytes into the packet.
	152	*
	153	* NOTES: Ditto the note for iso_check_csum().
	154	*/
	155
	156	void
	157	iso_gen_csum(m,n,l)
	158	struct mbuf *m;
	159	int n; /* offset of 2 checksum bytes */
	160	int l;
	161	{
ee8eb34a	162	register u_char p = mtod(m, u_char );
ee8eb34a KS	163	register int c0=0, c1=0;
	164	register int i=0;
	165	int loc = n++, len=0; /* n is position, loc is offset */
	166	u_char *xloc;
	167	u_char *yloc;
	168	int cum=0; /* cum == cumulative length */
	169
	170	IFDEBUG(D_CHKSUM)
	171	printf("enter gen csum m 0x%x n 0x%x l 0x%x\n",m, n-1 ,l );
	172	ENDDEBUG
	173
	174	while(i < l) {
8f8c8741	175	len = min(m->m_len, CLBYTES);
ee8eb34a	176	/* RAH: don't cksum more than l bytes */
8f8c8741	177	len = min(len, l - i);
ee8eb34a KS	178
	179	cum +=len;
	180	p = mtod(m, u_char *);
	181
	182	if(loc>=0) {
	183	if (loc < len) {
a50e2bc0	184	xloc = loc + mtod(m, u_char *);
ee8eb34a KS	185	IFDEBUG(D_CHKSUM)
	186	printf("1: zeroing xloc 0x%x loc 0x%x\n",xloc, loc );
	187	ENDDEBUG
	188	*xloc = (u_char)0;
	189	if (loc+1 < len) {
	190	/* both xloc and yloc are in same mbuf */
a50e2bc0	191	yloc = 1 + xloc;
ee8eb34a KS	192	IFDEBUG(D_CHKSUM)
	193	printf("2: zeroing yloc 0x%x loc 0x%x\n",yloc, loc );
	194	ENDDEBUG
	195	*yloc = (u_char)0;
	196	} else {
	197	/* crosses boundary of mbufs */
a50e2bc0	198	yloc = mtod(m->m_next, u_char *);
ee8eb34a KS	199	IFDEBUG(D_CHKSUM)
	200	printf("3: zeroing yloc 0x%x \n",yloc );
	201	ENDDEBUG
	202	*yloc = (u_char)0;
	203	}
	204	}
	205	loc -= len;
	206	}
	207
	208	while(i < cum) {
	209	c0 = (c0 + *p);
	210	c1 += c0 ;
	211	i++;
	212	p++;
	213	}
	214	m = m->m_next;
	215	}
	216	IFDEBUG(D_CHKSUM)
	217	printf("gen csum final xloc 0x%x yloc 0x%x\n",xloc, yloc );
	218	ENDDEBUG
	219
	220	c1 = (((c0 * (l-n))-c1)%255) ;
	221	*xloc = (u_char) ((c1 < 0)? c1+255 : c1);
	222
	223	c1 = (-(int)(c1+c0))%255;
	224	*yloc = (u_char) (c1 < 0? c1 + 255 : c1);
	225
	226	IFDEBUG(D_CHKSUM)
	227	printf("gen csum end \n");
	228	ENDDEBUG
	229	}
	230
ee8eb34a KS	231	/*
	232	* FUNCTION: m_datalen
	233	*
	234	* PURPOSE: returns length of the mbuf chain.
	235	* used all over the iso code.
	236	*
	237	* RETURNS: integer
	238	*
	239	* SIDE EFFECTS: none
	240	*
	241	* NOTES:
	242	*/
	243
	244	int
5af1395e KS	245	m_datalen (m)
5af1395e KS	246	register struct mbuf *m;
ee8eb34a	247	{
5af1395e	248	register int datalen;
ee8eb34a	249
5af1395e KS	250	for (datalen = 0; m; m = m->m_next)
5af1395e KS	251	datalen += m->m_len;
ee8eb34a KS	252	return datalen;
	253	}
	254
	255	int
	256	m_compress(in, out)
	257	register struct mbuf in, *out;
	258	{
	259	register int datalen = 0;
	260	int s = splimp();
	261
	262	if( in->m_next == MNULL ) {
	263	*out = in;
	264	IFDEBUG(D_REQUEST)
	265	printf("m_compress returning 0x%x: A\n", in->m_len);
	266	ENDDEBUG
	267	splx(s);
	268	return in->m_len;
	269	}
	270	MGET((*out), M_DONTWAIT, MT_DATA);
	271	if((*out) == MNULL) {
	272	*out = in;
	273	IFDEBUG(D_REQUEST)
	274	printf("m_compress returning -1: B\n");
	275	ENDDEBUG
	276	splx(s);
	277	return -1;
	278	}
	279	(*out)->m_len = 0;
	280	(*out)->m_act = MNULL;
	281
	282	while (in) {
	283	IFDEBUG(D_REQUEST)
	284	printf("m_compress in 0x%x out 0x%x\n", in, out);
a50e2bc0	285	printf("m_compress in: len 0x%x, off 0x%x\n", in->m_len, in->m_data);
ee8eb34a	286	printf("m_compress out: len 0x%x, off 0x%x\n", (out)->m_len,
a50e2bc0	287	(*out)->m_data);
ee8eb34a	288	ENDDEBUG
a50e2bc0	289	if (in->m_flags & M_EXT) {
ee8eb34a KS	290	ASSERT(in->m_len == 0);
	291	}
	292	if ( in->m_len == 0) {
	293	in = in->m_next;
	294	continue;
	295	}
a50e2bc0	296	if (((*out)->m_flags & M_EXT) == 0) {
ee8eb34a KS	297	int len;
ee8eb34a KS	298
a50e2bc0	299	len = M_TRAILINGSPACE(*out);
8f8c8741	300	len = min(len, in->m_len);
ee8eb34a KS	301	datalen += len;
	302
	303	IFDEBUG(D_REQUEST)
	304	printf("m_compress copying len %d\n", len);
	305	ENDDEBUG
a50e2bc0 KS	306	bcopy(mtod(in, caddr_t), mtod((out), caddr_t) + (out)->m_len,
a50e2bc0 KS	307	(unsigned)len);
ee8eb34a KS	308
	309	(*out)->m_len += len;
	310	in->m_len -= len;
	311	continue;
	312	} else {
	313	/* (out) is full /
	314	if(( (*out)->m_next = m_get(M_DONTWAIT, MT_DATA) ) == MNULL) {
	315	m_freem(*out);
	316	*out = in;
	317	IFDEBUG(D_REQUEST)
	318	printf("m_compress returning -1: B\n");
	319	ENDDEBUG
	320	splx(s);
	321	return -1;
	322	}
	323	(*out)->m_len = 0;
	324	(*out)->m_act = MNULL;
	325	out = (out)->m_next;
	326	}
	327	}
	328	m_freem(in);
	329	IFDEBUG(D_REQUEST)
	330	printf("m_compress returning 0x%x: A\n", datalen);
	331	ENDDEBUG
	332	splx(s);
	333	return datalen;
	334	}