Get rid of zero-length arrays in structures - they're not standard C89
and not all C compilers support them.
The minimum length of a SLARP packet is 14 bytes, not 18 bytes. SLARP
requests don't have any data, apparently.
diff --git a/print-chdlc.c b/print-chdlc.c
index b1c67cf..18b232a 100644
--- a/print-chdlc.c
+++ b/print-chdlc.c
@@ -21,7 +21,7 @@
#ifndef lint
static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/tcpdump/print-chdlc.c,v 1.35 2005-04-10 06:39:59 hannes Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/tcpdump/print-chdlc.c,v 1.36 2005-04-19 08:06:09 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@@ -112,6 +112,9 @@
return (CHDLC_HDRLEN);
}
+/*
+ * The fixed-length portion of a SLARP packet.
+ */
struct cisco_slarp {
u_int8_t code[4];
#define SLARP_REQUEST 0
@@ -126,12 +129,11 @@
u_int8_t myseq[4];
u_int8_t yourseq[4];
u_int8_t rel[2];
- u_int8_t time[0];
} keep;
} un;
};
-#define SLARP_LEN 18
+#define SLARP_LEN 14
static void
chdlc_slarp_print(const u_char *cp, u_int length)
@@ -144,12 +146,19 @@
goto trunc;
slarp = (const struct cisco_slarp *)cp;
- TCHECK(*slarp);
+ TCHECK2(*slarp, SLARP_LEN);
switch (EXTRACT_32BITS(&slarp->code)) {
case SLARP_REQUEST:
printf("request");
- /* ok we do not know it - but lets at least dump it */
- print_unknown_data(cp+4,"\n\t",length-4);
+ /*
+ * At least according to William "Chops" Westfield's
+ * message in
+ *
+ * http://www.nethelp.no/net/cisco-hdlc.txt
+ *
+ * the address and mask aren't used in requests -
+ * they're just zero.
+ */
break;
case SLARP_REPLY:
printf("reply %s/%s",
@@ -163,9 +172,10 @@
EXTRACT_16BITS(&slarp->un.keep.rel));
if (length >= SLARP_LEN) { /* uptime-stamp is optional */
- if (!TTEST2(slarp->un.keep.time, 4))
+ cp += SLARP_LEN;
+ if (!TTEST2(*cp, 4))
goto trunc;
- sec = EXTRACT_32BITS(&slarp->un.keep.time) / 1000;
+ sec = EXTRACT_32BITS(cp) / 1000;
min = sec / 60; sec -= min * 60;
hrs = min / 60; min -= hrs * 60;
days = hrs / 24; hrs -= days * 24;
