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Detect pred1 packets where the length != the packet length

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Use a maximum of MAX_MRU + 2 bytes for incoming packets, not
MAX_MTU + 2.
Tidy up some diagnostics.
This commit is contained in:
brian 1999-03-16 01:24:23 +00:00
parent ac59e661be
commit f7a7179f0f
1 changed files with 17 additions and 12 deletions
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29
usr.sbin/ppp/pred.c
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@ -26,7 +26,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: pred.c,v 1.22 1998/08/07 18:42:50 brian Exp $
* $Id: pred.c,v 1.23 1999/03/11 01:49:15 brian Exp $
*/
#include <sys/types.h>
@ -87,17 +87,16 @@ compress(struct pred1_state *state, u_char *source, u_char *dest, int len)
}
static void
SyncTable(struct pred1_state *state, u_char * source, u_char * dest, int len)
SyncTable(struct pred1_state *state, u_char *source, u_char *dest, int len)
{
while (len--) {
if (state->dict[state->hash] != *source)
state->dict[state->hash] = *source;
HASH(state, *dest++ = *source++);
*dest++ = state->dict[state->hash] = *source;
HASH(state, *source++);
}
}
static int
decompress(struct pred1_state *state, u_char * source, u_char * dest, int len)
decompress(struct pred1_state *state, u_char *source, u_char *dest, int len)
{
int i, bitmask;
unsigned char flags, *orgdest;
@ -220,7 +219,7 @@ Pred1Input(void *v, struct ccp *ccp, u_short *proto, struct mbuf *bp)
u_char *bufp;
u_short fcs;
wp = mbuf_Alloc(MAX_MTU + 2, MB_IPIN);
wp = mbuf_Alloc(MAX_MRU + 2, MB_IPIN);
cp = MBUF_CTOP(bp);
olen = mbuf_Length(bp);
pp = bufp = MBUF_CTOP(wp);
@ -242,6 +241,12 @@ Pred1Input(void *v, struct ccp *ccp, u_short *proto, struct mbuf *bp)
}
cp += olen - 4;
pp += len1;
} else if (len + 4 != olen) {
log_Printf(LogCCP, "Pred1: Length error (got %d, not %d)\n", len + 4, olen);
fsm_Reopen(&ccp->fsm);
mbuf_Free(wp);
mbuf_Free(bp);
return NULL;
} else {
ccp->compin += len;
SyncTable(state, cp, pp, len);
@ -251,10 +256,6 @@ Pred1Input(void *v, struct ccp *ccp, u_short *proto, struct mbuf *bp)
*pp++ = *cp++; /* CRC */
*pp++ = *cp++;
fcs = hdlc_Fcs(INITFCS, bufp, wp->cnt = pp - bufp);
if (fcs != GOODFCS)
log_Printf(LogDEBUG, "Pred1Input: fcs = 0x%04x (%s), len = 0x%x,"
" olen = 0x%x\n", fcs, (fcs == GOODFCS) ? "good" : "bad",
len, olen);
if (fcs == GOODFCS) {
wp->offset += 2; /* skip length */
wp->cnt -= 4; /* skip length & CRC */
@ -271,7 +272,11 @@ Pred1Input(void *v, struct ccp *ccp, u_short *proto, struct mbuf *bp)
mbuf_Free(bp);
return wp;
} else {
log_Printf(LogCCP, "%s: Bad CRC-16\n", ccp->fsm.link->name);
const char *pre = *MBUF_CTOP(bp) & 0x80 ? "" : "un";
log_Printf(LogDEBUG, "Pred1Input: fcs = 0x%04x (%scompressed), len = 0x%x,"
" olen = 0x%x\n", fcs, pre, len, olen);
log_Printf(LogCCP, "%s: Bad %scompressed CRC-16\n",
ccp->fsm.link->name, pre);
fsm_Reopen(&ccp->fsm);
mbuf_Free(wp);
}