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-rw-r--r--print-mpls.c174
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+/*
+ * Copyright (C) 2001 WIDE Project. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the project nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/* \summary: Multi-Protocol Label Switching (MPLS) printer */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#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",
+ "implicit NULL", "rsvd",
+/*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
+/*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
+/*15*/ "rsvd",
+};
+
+enum mpls_packet_type {
+ PT_UNKNOWN,
+ PT_IPV4,
+ PT_IPV6,
+ PT_OSI
+};
+
+/*
+ * RFC3032: MPLS label stack encoding
+ */
+void
+mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
+{
+ const u_char *p;
+ 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;
+ nd_print_protocol_caps(ndo);
+ do {
+ 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 */
+ pt = PT_IPV4;
+ break;
+
+ case 2: /* IPv6 explicit NULL label */
+ pt = PT_IPV6;
+ break;
+
+ default:
+ /*
+ * Generally there's no indication of protocol in MPLS label
+ * 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;
+ }
+
+ /*
+ * 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;
+
+invalid:
+ nd_print_invalid(ndo);
+ ND_TCHECK_LEN(p, length);
+}