* SUCH DAMAGE.
*/
-#ifndef lint
-static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.11 2004-06-06 19:20:04 hannes Exp $ (LBL)";
-#endif
-
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <tcpdump-stdinc.h>
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "addrtoname.h"
-#include "interface.h"
-#include "extract.h" /* must come after interface.h */
-
-#define LABEL_MASK 0xfffff000
-#define LABEL_SHIFT 12
-#define EXP_MASK 0x00000e00
-#define EXP_SHIFT 9
-#define STACK_MASK 0x00000100
-#define STACK_SHIFT 8
-#define TTL_MASK 0x000000ff
-#define TTL_SHIFT 0
-
-#define MPLS_LABEL(x) (((x) & LABEL_MASK) >> LABEL_SHIFT)
-#define MPLS_EXP(x) (((x) & EXP_MASK) >> EXP_SHIFT)
-#define MPLS_STACK(x) (((x) & STACK_MASK) >> STACK_SHIFT)
-#define MPLS_TTL(x) (((x) & TTL_MASK) >> TTL_SHIFT)
+/* \summary: Multi-Protocol Label Switching (MPLS) printer */
+
+#include <config.h>
+
+#include "netdissect-stdinc.h"
+
+#define ND_LONGJMP_FROM_TCHECK
+#include "netdissect.h"
+#include "extract.h"
+#include "mpls.h"
static const char *mpls_labelname[] = {
/*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
/*15*/ "rsvd",
};
+enum mpls_packet_type {
+ PT_UNKNOWN,
+ PT_IPV4,
+ PT_IPV6,
+ PT_OSI
+};
+
/*
* RFC3032: MPLS label stack encoding
*/
void
-mpls_print(const u_char *bp, u_int length)
+mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
{
const u_char *p;
- u_int32_t v;
+ uint32_t label_entry;
+ uint16_t label_stack_depth = 0;
+ uint8_t first;
+ enum mpls_packet_type pt = PT_UNKNOWN;
+ ndo->ndo_protocol = "mpls";
p = bp;
- printf("MPLS");
+ nd_print_protocol_caps(ndo);
do {
- TCHECK2(*p, sizeof(v));
- v = EXTRACT_32BITS(p);
- printf(" ("); /*)*/
- printf("label %u", MPLS_LABEL(v));
- if (vflag &&
- MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
- printf(" (%s)", mpls_labelname[MPLS_LABEL(v)]);
- printf(", exp %u", MPLS_EXP(v));
- if (MPLS_STACK(v))
- printf(", [S]");
- printf(", ttl %u", MPLS_TTL(v));
- /*(*/
- printf(")");
-
- p += sizeof(v);
- } while (!MPLS_STACK(v));
-
- switch (MPLS_LABEL(v)) {
+ if (length < sizeof(label_entry))
+ goto invalid;
+ label_entry = GET_BE_U_4(p);
+ ND_PRINT("%s(label %u",
+ (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
+ MPLS_LABEL(label_entry));
+ label_stack_depth++;
+ if (ndo->ndo_vflag &&
+ MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
+ ND_PRINT(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
+ ND_PRINT(", tc %u", MPLS_TC(label_entry));
+ if (MPLS_STACK(label_entry))
+ ND_PRINT(", [S]");
+ ND_PRINT(", ttl %u)", MPLS_TTL(label_entry));
+
+ p += sizeof(label_entry);
+ length -= sizeof(label_entry);
+ } while (!MPLS_STACK(label_entry));
+
+ /*
+ * Try to figure out the packet type.
+ */
+ switch (MPLS_LABEL(label_entry)) {
+
case 0: /* IPv4 explicit NULL label */
- case 3: /* IPv4 implicit NULL label */
- ip_print(p, length - (p - bp));
+ case 3: /* IPv4 implicit NULL label */
+ pt = PT_IPV4;
break;
-#ifdef INET6
+
case 2: /* IPv6 explicit NULL label */
- ip6_print(p, length - (p - bp));
+ pt = PT_IPV6;
break;
-#endif
+
default:
/*
* Generally there's no indication of protocol in MPLS label
- * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
- * a technique that looks at the first payload byte if the BOS (bottom of stack)
- * bit is set and tries to determine the network layer protocol
- * 0x45-0x4f is IPv4
- * 0x60-0x6f is IPv6
- * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
- * this technique is sometimes known as NULL encapsulation
- * and decoding is particularly useful for control-plane traffic [BGP]
- * which cisco by default sends MPLS encapsulated
+ * encoding.
+ *
+ * However, draft-hsmit-isis-aal5mux-00.txt describes a
+ * technique for encapsulating IS-IS and IP traffic on the
+ * same ATM virtual circuit; you look at the first payload
+ * byte to determine the network layer protocol, based on
+ * the fact that
+ *
+ * 1) the first byte of an IP header is 0x45-0x4f
+ * for IPv4 and 0x60-0x6f for IPv6;
+ *
+ * 2) the first byte of an OSI CLNP packet is 0x81,
+ * the first byte of an OSI ES-IS packet is 0x82,
+ * and the first byte of an OSI IS-IS packet is
+ * 0x83;
+ *
+ * so the network layer protocol can be inferred from the
+ * first byte of the packet, if the protocol is one of the
+ * ones listed above.
+ *
+ * Cisco sends control-plane traffic MPLS-encapsulated in
+ * this fashion.
*/
+ if (length < 1) {
+ /* nothing to print */
+ return;
+ }
+ first = GET_U_1(p);
+ pt =
+ (first >= 0x45 && first <= 0x4f) ? PT_IPV4 :
+ (first >= 0x60 && first <= 0x6f) ? PT_IPV6 :
+ (first >= 0x81 && first <= 0x83) ? PT_OSI :
+ /* ok bail out - we did not figure out what it is*/
+ PT_UNKNOWN;
+ }
- if (MPLS_STACK(v)) { /* only do this if the stack bit is set */
- switch(*p) {
- case 0x45:
- case 0x46:
- case 0x47:
- case 0x48:
- case 0x49:
- case 0x4a:
- case 0x4b:
- case 0x4c:
- case 0x4d:
- case 0x4e:
- case 0x4f:
- if (vflag>0) {
- printf("\n\t");
- ip_print(p, length - (p - bp));
- }
- else printf(", IP, length: %u",length);
- break;
-#ifdef INET6
- case 0x60:
- case 0x61:
- case 0x62:
- case 0x63:
- case 0x64:
- case 0x65:
- case 0x66:
- case 0x67:
- case 0x68:
- case 0x69:
- case 0x6a:
- case 0x6b:
- case 0x6c:
- case 0x6d:
- case 0x6e:
- case 0x6f:
- if (vflag>0) {
- printf("\n\t");
- ip6_print(p, length - (p - bp));
- }
- else printf(", IPv6, length: %u",length);
- break;
-#endif
- case 0x81:
- case 0x82:
- case 0x83:
- if (vflag>0) {
- printf("\n\t");
- isoclns_print(p, length - (p - bp), length - (p - bp));
- }
- else printf(", OSI, length: %u",length);
- break;
- default:
- /* ok bail out - we did not figure out what it is*/
- break;
- }
- }
- return;
+ /*
+ * Print the payload.
+ */
+ switch (pt) {
+ case PT_UNKNOWN:
+ if (!ndo->ndo_suppress_default_print)
+ ND_DEFAULTPRINT(p, length);
+ break;
+
+ case PT_IPV4:
+ ND_PRINT(ndo->ndo_vflag ? "\n\t" : " ");
+ ip_print(ndo, p, length);
+ break;
+
+ case PT_IPV6:
+ ND_PRINT(ndo->ndo_vflag ? "\n\t" : " ");
+ ip6_print(ndo, p, length);
+ break;
+
+ case PT_OSI:
+ ND_PRINT(ndo->ndo_vflag ? "\n\t" : " ");
+ isoclns_print(ndo, p, length);
+ break;
}
+ return;
-trunc:
- printf("[|MPLS]");
+invalid:
+ nd_print_invalid(ndo);
+ ND_TCHECK_LEN(p, length);
}
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