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Diffstat (limited to 'sys/netiso/iso_chksum.c')
| -rw-r--r-- | sys/netiso/iso_chksum.c | 360 |
1 files changed, 360 insertions, 0 deletions
diff --git a/sys/netiso/iso_chksum.c b/sys/netiso/iso_chksum.c new file mode 100644 index 0000000..5b1aae5 --- /dev/null +++ b/sys/netiso/iso_chksum.c @@ -0,0 +1,360 @@ +/*- + * Copyright (c) 1991, 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. + * + * @(#)iso_chksum.c 8.1 (Berkeley) 6/10/93 + */ + +/*********************************************************** + 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; +} |
