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Point at cs.slcs_u.csu_ip instead of the just-copied ``cp''

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when recalculating the ip checksum.  cp is not guaranteed to
be aligned.  It now doesn't matter that cp isn't aligned as
the caller does another mbuf_Alloc() regardless.
This commit is contained in:
brian 1999-03-30 07:57:22 +00:00
parent b3def447d1
commit 2c5f507432
1 changed files with 9 additions and 19 deletions
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28
usr.sbin/ppp/slcompress.c
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@ -17,7 +17,7 @@
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $Id: slcompress.c,v 1.20 1998/08/26 17:39:37 brian Exp $
* $Id: slcompress.c,v 1.21 1999/01/28 01:56:34 brian Exp $
*
* Van Jacobson (van@helios.ee.lbl.gov), Dec 31, 1989:
* - Initial distribution.
@ -447,13 +447,14 @@ sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp,
case TYPE_COMPRESSED_TCP:
break;
}
/* We've got a compressed packet. */
slstat->sls_compressedin++;
cp = *bufp;
changes = *cp++;
log_Printf(LogDEBUG, "compressed: changes = %02x\n", changes);
if (changes & NEW_C) {
if (changes & NEW_C) {
/*
* Make sure the state index is in range, then grab the state. If we have
* a good state index, clear the 'discard' flag.
@ -465,7 +466,6 @@ sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp,
comp->flags &= ~SLF_TOSS;
comp->last_recv = *cp++;
} else {
/*
* this packet has an implicit state index. If we've had a line error
* since the last time we got an explicit state index, we have to toss
@ -529,30 +529,20 @@ sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp,
cs->cs_ip.ip_id, (u_long)ntohl(th->th_seq));
/*
* At this point, cp points to the first byte of data in the packet. If
* we're not aligned on a 4-byte boundary, copy the data down so the ip &
* tcp headers will be aligned. Then back up cp by the tcp/ip header
* length to make room for the reconstructed header (we assume the packet
* we were handed has enough space to prepend 128 bytes of header). Adjust
* the length to account for the new header & fill in the IP total length.
* At this point, cp points to the first byte of data in the packet.
* Back up cp by the tcp/ip header length to make room for the
* reconstructed header (we assume the packet we were handed has enough
* space to prepend 128 bytes of header). Adjust the length to account
* for the new header & fill in the IP total length.
*/
len -= (cp - *bufp);
if (len < 0)
/*
* we must have dropped some characters (crc should detect this but the
* old slip framing won't)
*/
goto bad;
#ifdef notdef
if ((int) cp & 3) {
if (len > 0)
(void) bcopy(cp, (caddr_t) ((int) cp & ~3), len);
cp = (u_char *) ((int) cp & ~3);
}
#endif
cp -= cs->cs_hlen;
len += cs->cs_hlen;
cs->cs_ip.ip_len = htons(len);
@ -561,7 +551,7 @@ sl_uncompress_tcp(u_char ** bufp, int len, u_int type, struct slcompress *comp,
/* recompute the ip header checksum */
{
register u_short *bp = (u_short *) cp;
register u_short *bp = (u_short *)&cs->cs_ip;
for (changes = 0; hlen > 0; hlen -= 2)
changes += *bp++;