* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+/* \summary: PPP Van Jacobson compression printer */
-#if defined(__bsdi__)
+/* specification: RFC 1144 */
-#ifndef lint
-static const char rcsid[] =
- "@(#) $Header: /tcpdump/master/tcpdump/print-vjc.c,v 1.4 2000-07-01 03:39:11 assar Exp $ (LBL)";
-#endif
+#include <config.h>
-#include <sys/param.h>
-#include <sys/time.h>
-#include <sys/socket.h>
-#include <sys/file.h>
-#include <sys/ioctl.h>
+#include "netdissect-stdinc.h"
-struct mbuf;
-struct rtentry;
-#include <net/if.h>
-
-#include <netinet/in.h>
-#include <netinet/in_systm.h>
-#include <netinet/ip.h>
-#include <netinet/if_ether.h>
-
-#include <ctype.h>
-#include <netdb.h>
-#include <pcap.h>
-#include <stdio.h>
-
-#if defined(__NetBSD__)
-#include <sys/mbuf.h>
-#include <net/ppp_defs.h>
-#endif
-
-#if defined(__bsdi__) || defined(__NetBSD__)
-#include <net/if_ppp.h>
-#include <net/slcompress.h>
-#endif
-
-#include "interface.h"
-#include "addrtoname.h"
+#include "netdissect.h"
+#include "extract.h"
+#include "slcompress.h"
+#include "ppp.h"
+/*
+ * XXX - for BSD/OS PPP, what packets get supplied with a PPP header type
+ * of PPP_VJC and what packets get supplied with a PPP header type of
+ * PPP_VJNC? PPP_VJNC is for "UNCOMPRESSED_TCP" packets, and PPP_VJC
+ * is for COMPRESSED_TCP packets (PPP_IP is used for TYPE_IP packets).
+ *
+ * RFC 1144 implies that, on the wire, the packet type is *not* needed
+ * for PPP, as different PPP protocol types can be used; it only needs
+ * to be put on the wire for SLIP.
+ *
+ * It also indicates that, for compressed SLIP:
+ *
+ * If the COMPRESSED_TCP bit is set in the first byte, it's
+ * a COMPRESSED_TCP packet; that byte is the change byte, and
+ * the COMPRESSED_TCP bit, 0x80, isn't used in the change byte.
+ *
+ * If the upper 4 bits of the first byte are 7, it's an
+ * UNCOMPRESSED_TCP packet; that byte is the first byte of
+ * the UNCOMPRESSED_TCP modified IP header, with a connection
+ * number in the protocol field, and with the version field
+ * being 7, not 4.
+ *
+ * Otherwise, the packet is an IPv4 packet (where the upper 4 bits
+ * of the packet are 4).
+ *
+ * So this routine looks as if it's sort-of intended to handle
+ * compressed SLIP, although it doesn't handle UNCOMPRESSED_TCP
+ * correctly for that (it doesn't fix the version number and doesn't
+ * do anything to the protocol field), and doesn't check for COMPRESSED_TCP
+ * packets correctly for that (you only check the first bit - see
+ * B.1 in RFC 1144).
+ *
+ * But it's called for BSD/OS PPP, not SLIP - perhaps BSD/OS does weird
+ * things with the headers?
+ *
+ * Without a BSD/OS VJC-compressed PPP trace, or knowledge of what the
+ * BSD/OS VJC code does, we can't say what's the case.
+ *
+ * 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(register const char *bp, register u_int length, u_short proto)
+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 (eflag)
- printf("(vjc type=IP) ");
+ if (ndo->ndo_eflag)
+ ND_PRINT("(vjc type=IP) ");
return PPP_IP;
case TYPE_UNCOMPRESSED_TCP:
- if (eflag)
- printf("(vjc type=raw TCP) ");
+ if (ndo->ndo_eflag)
+ ND_PRINT("(vjc type=raw TCP) ");
return PPP_IP;
case TYPE_COMPRESSED_TCP:
- if (eflag)
- printf("(vjc type=compressed TCP) ");
+ if (ndo->ndo_eflag)
+ ND_PRINT("(vjc type=compressed TCP) ");
for (i = 0; i < 8; i++) {
- if (bp[1] & (0x80 >> i))
- printf("%c", "?CI?SAWU"[i]);
+ if (GET_U_1(bp + 1) & (0x80 >> i))
+ ND_PRINT("%c", "?CI?SAWU"[i]);
}
- if (bp[1])
- printf(" ");
- printf("C=0x%02x ", bp[2]);
- printf("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 (eflag)
- printf("(vjc type=error) ");
+ if (ndo->ndo_eflag)
+ ND_PRINT("(vjc type=error) ");
return -1;
default:
- if (eflag)
- printf("(vjc type=0x%02x) ", bp[0] & 0xf0);
+ if (ndo->ndo_eflag)
+ ND_PRINT("(vjc type=0x%02x) ", GET_U_1(bp) & 0xf0);
return -1;
}
}
-#endif /* defined(__bsdi__) || defined(__NetBSD__) */
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