* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+/* \summary: PPP Van Jacobson compression printer */
-#include <tcpdump-stdinc.h>
+/* specification: RFC 1144 */
+
+#include <config.h>
+
+#include "netdissect-stdinc.h"
#include "netdissect.h"
+#include "extract.h"
#include "slcompress.h"
#include "ppp.h"
* We therefore leave "proto" - which is the PPP protocol type - in place,
* *not* marked as unused, for now, so that GCC warnings about the
* unused argument remind us that we should fix this some day.
+ *
+ * XXX - also, it fetches the TCP checksum field in COMPRESSED_TCP
+ * packets with GET_HE_U_2, rather than with GET_BE_U_2(); RFC 1144 says
+ * it's "the unmodified TCP checksum", which would imply that it's
+ * big-endian, but perhaps, on the platform where this was developed,
+ * the packets were munged by the networking stack before being handed
+ * to the packet capture mechanism.
*/
int
-vjc_print(netdissect_options *ndo, register const char *bp, u_short proto _U_)
+vjc_print(netdissect_options *ndo, const u_char *bp, u_short proto _U_)
{
int i;
- switch (bp[0] & 0xf0) {
+ ndo->ndo_protocol = "vjc";
+ switch (GET_U_1(bp) & 0xf0) {
case TYPE_IP:
if (ndo->ndo_eflag)
- ND_PRINT((ndo, "(vjc type=IP) "));
+ ND_PRINT("(vjc type=IP) ");
return PPP_IP;
case TYPE_UNCOMPRESSED_TCP:
if (ndo->ndo_eflag)
- ND_PRINT((ndo, "(vjc type=raw TCP) "));
+ ND_PRINT("(vjc type=raw TCP) ");
return PPP_IP;
case TYPE_COMPRESSED_TCP:
if (ndo->ndo_eflag)
- ND_PRINT((ndo, "(vjc type=compressed TCP) "));
+ ND_PRINT("(vjc type=compressed TCP) ");
for (i = 0; i < 8; i++) {
- if (bp[1] & (0x80 >> i))
- ND_PRINT((ndo, "%c", "?CI?SAWU"[i]));
+ if (GET_U_1(bp + 1) & (0x80 >> i))
+ ND_PRINT("%c", "?CI?SAWU"[i]);
}
- if (bp[1])
- ND_PRINT((ndo, " "));
- ND_PRINT((ndo, "C=0x%02x ", bp[2]));
- ND_PRINT((ndo, "sum=0x%04x ", *(u_short *)&bp[3]));
+ if (GET_U_1(bp + 1))
+ ND_PRINT(" ");
+ ND_PRINT("C=0x%02x ", GET_U_1(bp + 2));
+ ND_PRINT("sum=0x%04x ", GET_HE_U_2(bp + 3));
return -1;
case TYPE_ERROR:
if (ndo->ndo_eflag)
- ND_PRINT((ndo, "(vjc type=error) "));
+ ND_PRINT("(vjc type=error) ");
return -1;
default:
if (ndo->ndo_eflag)
- ND_PRINT((ndo, "(vjc type=0x%02x) ", bp[0] & 0xf0));
+ ND_PRINT("(vjc type=0x%02x) ", GET_U_1(bp) & 0xf0);
return -1;
}
}