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Diffstat (limited to '')
| -rw-r--r-- | print-mpls.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/print-mpls.c b/print-mpls.c new file mode 100644 index 0000000..c9be496 --- /dev/null +++ b/print-mpls.c @@ -0,0 +1,174 @@ +/* + * 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); +} |