/*      $OpenBSD: print-mpls.c,v 1.4 2018/07/06 07:00:49 dlg Exp $      */

/*
 * Copyright (c) 2005 Jason L. Wright (jason@thought.net)
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#include <sys/socket.h>
#include <sys/types.h>
#include <netmpls/mpls.h>

#include <stdio.h>

#include "interface.h"
#include "extract.h"                /* must come after interface.h */

#define CW_SEQUENCE_MASK       (0x0000ffffU)

int controlword_tryprint(const u_char **, u_int *);

void
mpls_print(const u_char *bp, u_int len)
{
        u_int32_t tag, label, exp, bottom, ttl;
        int has_cw;

        do {
                if (bp + sizeof(tag) > snapend)
                        goto trunc;

                tag = EXTRACT_32BITS(bp);
                bp += sizeof(tag);
                len -= sizeof(tag);

                label = (tag >> 12) & 0xfffff;
                exp = (tag >> 9) & 0x7;
                bottom = (tag >> 8) & 0x1;
                ttl = (tag >> 0) & 0xff;

                printf("MPLS(label %u, exp %u, ttl %u) ", label, exp, ttl);

                /* XXX decode "Router Alert Label" */
        } while (!bottom);

        /* Handle pseudowire control word. */
        has_cw = controlword_tryprint(&bp, &len);

        /*
         * guessing the underlying protocol is about all we can do if
         * it's not explicitly defined.
         */

        switch (label) {
        case 0x00000:                   /* IPv4 Explicit NULL */
                ip_print(bp, len);
                break;
        case 0x00001:                   /* Router Alert */
                /* shouldn't happen at stack bottom */
                printf("Route-Alert");
                break;
        case 0x00002:                   /* IPv6 Explicit NULL */
                ip6_print(bp, len);
                break;
        case 0x00003:                   /* Implicit NULL */
                /* shouldn't happen in the tag stack */
                printf("Implicit-NULL");
                break;

        case 0x00004:                   /* reserved labels */
        case 0x00005:
        case 0x00006:
        case 0x00007:
        case 0x00008:
        case 0x00009:
        case 0x0000a:
        case 0x0000b:
        case 0x0000c:
        case 0x0000d:
        case 0x0000e:
        case 0x0000f:
                break;

        default:                        /* dunno, guess? */
                if (len == 0)
                        break;
                if (bp >= snapend)
                        goto trunc;

                switch (bp[0] & 0xf0) {
                case 0x40:
                        ip_print(bp, len);
                        break;
                case 0x60:
                        ip6_print(bp, len);
                        break;
                }
        }

        if (has_cw)
                ether_tryprint(bp, len, 0);

        return;
trunc:
        printf("[|mpls]");
}

/* Print control word if any and returns 1 on success. */
int
controlword_tryprint(const u_char **bp, u_int *lenp)
{
        uint32_t cw, frag, seq;

        if (*lenp < 4)
                return (0);

        cw = EXTRACT_32BITS(*bp);
        if (cw & CW_ZERO_MASK)
                return (0);

        *bp += sizeof(cw);
        *lenp += sizeof(cw);

        frag = (cw & CW_FRAG_MASK) >> 16;
        seq = cw & CW_SEQUENCE_MASK;

        printf("CW(frag %u, sequence %u) ", frag, seq);

        return (1);
}